diff --git a/bitchat/Services/MessageFormattingEngine.swift b/bitchat/Services/MessageFormattingEngine.swift
index 88a32e3c..adb7f2c4 100644
--- a/bitchat/Services/MessageFormattingEngine.swift
+++ b/bitchat/Services/MessageFormattingEngine.swift
@@ -368,8 +368,44 @@ final class MessageFormattingEngine {
             allMatches.append(ContentMatch(range: match.range(at: 0), type: .lnurl))
         }
 
-        // Sort by position
-        return allMatches.sorted { $0.range.location < $1.range.location }
+        // The per-type checks above only guard specific known pairs (e.g.
+        // bolt11/lnurl against url/lightning) -- they don't cover every
+        // combination, so an ordinary message can still produce overlapping
+        // matches of two OTHER types the checks never compared (e.g. a URL
+        // whose path embeds a "cashuA..."-shaped token). Resolve any
+        // remaining overlap before handing matches to a rendering pass.
+        return resolveOverlappingMatches(allMatches) { $0.range }
+    }
+
+    /// Sorts matches by start position and greedily keeps only non-overlapping
+    /// ones, dropping any later match whose start falls inside an
+    /// already-kept match's range. Rendering passes that consume the result
+    /// (here and in `ChatMessageFormatter`, which has its own copy of the
+    /// match-collection logic above) assume non-overlapping,
+    /// strictly-increasing ranges; without this resolution a nested match
+    /// re-renders already-shown text and can walk the render cursor
+    /// backwards, duplicating a trailing slice of content a second time.
+    ///
+    /// Ties break by start position only, not length: whichever match starts
+    /// first wins outright, so an outer match (e.g. a URL) always keeps
+    /// priority over a shorter match nested inside it (e.g. an embedded cashu
+    /// token) rather than the other way around. That's intentional for
+    /// rendering — flip it to prefer the inner match only with a matching
+    /// change to how callers render the dropped outer span.
+    static func resolveOverlappingMatches<Match>(
+        _ matches: [Match],
+        range: (Match) -> NSRange
+    ) -> [Match] {
+        let sorted = matches.sorted { range($0).location < range($1).location }
+        var resolved: [Match] = []
+        var occupiedUntil = 0
+        for match in sorted {
+            let matchRange = range(match)
+            guard matchRange.location >= occupiedUntil else { continue }
+            resolved.append(match)
+            occupiedUntil = matchRange.location + matchRange.length
+        }
+        return resolved
     }
 
     private static func formatPlainContent(_ content: String, baseColor: Color, isSelf: Bool) -> AttributedString {
diff --git a/bitchat/ViewModels/ChatMessageFormatter.swift b/bitchat/ViewModels/ChatMessageFormatter.swift
index 1a00315b..b6653ab6 100644
--- a/bitchat/ViewModels/ChatMessageFormatter.swift
+++ b/bitchat/ViewModels/ChatMessageFormatter.swift
@@ -188,13 +188,23 @@ final class ChatMessageFormatter {
                 where !overlapsMention(match.range(at: 0)) && !overlapsOccupied(match.range(at: 0)) {
                     allMatches.append((match.range(at: 0), "lnurl"))
                 }
-                allMatches.sort { $0.range.location < $1.range.location }
+
+                // The per-type checks above only guard specific known pairs
+                // (e.g. bolt11/lnurl against url+lightning); they don't
+                // cover every combination, so an ordinary message can still
+                // produce overlapping matches of two OTHER types (e.g. a URL
+                // whose path embeds a "cashuA..."-shaped token). The render
+                // loop below assumes non-overlapping, strictly-increasing
+                // ranges; without resolving those first, a nested
+                // cashu/lightning match renders as an extra spacer character
+                // injected into already-shown text instead of being skipped.
+                let resolvedMatches = MessageFormattingEngine.resolveOverlappingMatches(allMatches) { $0.range }
 
                 var lastEnd = content.startIndex
                 let myNickname = viewModel.nickname.normalizedNickname
                 let isMentioned = message.mentions?.contains { $0.normalizedNickname == myNickname } ?? false
 
-                for (range, type) in allMatches {
+                for (range, type) in resolvedMatches {
                     guard let swiftRange = Range(range, in: content) else { continue }
 
                     if lastEnd < swiftRange.lowerBound {
diff --git a/bitchatTests/MessageFormattingEngineTests.swift b/bitchatTests/MessageFormattingEngineTests.swift
index 5de2adea..f32cd69a 100644
--- a/bitchatTests/MessageFormattingEngineTests.swift
+++ b/bitchatTests/MessageFormattingEngineTests.swift
@@ -349,6 +349,69 @@ struct MessageFormattingEngineTests {
 
         #expect(String(formatted.characters) == "<@alice> \(longContent) [\(message.formattedTimestamp)]")
     }
+
+    @MainActor
+    @Test func formatMessage_urlContainingCashuTokenIsNotDuplicated() {
+        // Bug: a URL match and a Cashu match are never cross-checked for
+        // overlap, only each independently against mentions. A URL whose
+        // path embeds a "cashuA..."-shaped segment (a perfectly ordinary
+        // mint redemption link) produces two overlapping matches; the
+        // single linear rendering pass then re-renders the nested cashu
+        // substring a second time and, because it walks `lastEnd` backwards,
+        // re-renders the URL's own trailing segment a third time.
+        let context = MockMessageFormattingContext(nickname: "carol")
+        let cashuToken = "cashuA" + String(repeating: "a", count: 44)
+        let url = "https://mint.example.com/redeem/\(cashuToken)/confirm"
+        let content = "redeem link \(url) now"
+        let message = BitchatMessage(
+            id: "url-cashu",
+            sender: "alice",
+            content: content,
+            timestamp: Date(timeIntervalSince1970: 1_700_001_111),
+            isRelay: false
+        )
+
+        let formatted = MessageFormattingEngine.formatMessage(message, context: context, colorScheme: .light)
+
+        #expect(String(formatted.characters) == "<@alice> \(content) [\(message.formattedTimestamp)]")
+    }
+
+    // MARK: - resolveOverlappingMatches Tests
+    //
+    // Direct coverage for the shared helper `ChatMessageFormatter` also
+    // calls, since its own match-collection logic (a hand-copy of
+    // findAllMatches above) isn't independently unit-testable without a
+    // live ChatViewModel.
+
+    @Test func resolveOverlappingMatches_dropsANestedOverlap() {
+        let outer = (range: NSRange(location: 0, length: 10), type: "outer")
+        let nested = (range: NSRange(location: 3, length: 2), type: "nested")
+
+        let resolved = MessageFormattingEngine.resolveOverlappingMatches([outer, nested]) { $0.range }
+
+        #expect(resolved.map(\.type) == ["outer"])
+    }
+
+    @Test func resolveOverlappingMatches_keepsNonOverlappingMatchesSortedByStart() {
+        let first = (range: NSRange(location: 0, length: 3), type: "first")
+        let second = (range: NSRange(location: 5, length: 3), type: "second")
+
+        // Passed out of order; the helper must sort internally.
+        let resolved = MessageFormattingEngine.resolveOverlappingMatches([second, first]) { $0.range }
+
+        #expect(resolved.map(\.type) == ["first", "second"])
+    }
+
+    @Test func resolveOverlappingMatches_adjacentNonOverlappingMatchesAreBothKept() {
+        // A match starting exactly where the previous one ends is not an
+        // overlap (NSRange upper bound is exclusive).
+        let first = (range: NSRange(location: 0, length: 5), type: "first")
+        let adjacent = (range: NSRange(location: 5, length: 5), type: "adjacent")
+
+        let resolved = MessageFormattingEngine.resolveOverlappingMatches([first, adjacent]) { $0.range }
+
+        #expect(resolved.map(\.type) == ["first", "adjacent"])
+    }
 }
 
 @MainActor