diff --git a/Libraries/LibRegex/RegexOptimizer.cpp b/Libraries/LibRegex/RegexOptimizer.cpp
index 9ef997ec5c7..69eaa930ab8 100644
--- a/Libraries/LibRegex/RegexOptimizer.cpp
+++ b/Libraries/LibRegex/RegexOptimizer.cpp
@@ -1560,7 +1560,7 @@ void Optimizer::append_alternation(ByteCode& target, Span<ByteCode> alternatives
                             target.append(static_cast<ByteCodeValueType>(OpCodeId::ForkJump));
                             patch_location = target.size();
                             should_negate = false;
-                            patch_size = 2;
+                            patch_size = 1;
                             target.append(static_cast<ByteCodeValueType>(0));
                         }
 
diff --git a/Tests/LibRegex/Regex.cpp b/Tests/LibRegex/Regex.cpp
index 438864ec09e..ea43a2ee472 100644
--- a/Tests/LibRegex/Regex.cpp
+++ b/Tests/LibRegex/Regex.cpp
@@ -1137,6 +1137,8 @@ TEST_CASE(optimizer_alternation)
         Tuple { "(xxxxxxxxxxxxxxxxxxxxxxx|xxxxxxxxxxxxxxxxxxxxxxx)?b"sv, "xxxxxxxxxxxxxxxxxxxxxxx"sv, 0u },
         // Don't take the jump in JumpNonEmpty with nonexistent checkpoints (also don't crash).
         Tuple { "(?!\\d*|[g-ta-r]+|[h-l]|\\S|\\S|\\S){,9}|\\S{7,8}|\\d|(?<wnvdfimiwd>)|[c-mj-tb-o]*|\\s"sv, "rjvogg7pm|li4nmct mjb2|pk7s8e0"sv, 0u },
+        // Use the right offset when patching jumps through a fork-tree
+        Tuple { "(?!a)|(?!a)b"sv, "b"sv, 0u },
     };
 
     for (auto& test : tests) {