diff --git a/frontend/test-client/src/agent/mock-agent.ts b/frontend/test-client/src/agent/mock-agent.ts
index c3f08b5b..d4fc8c82 100644
--- a/frontend/test-client/src/agent/mock-agent.ts
+++ b/frontend/test-client/src/agent/mock-agent.ts
@@ -336,21 +336,18 @@ export class MockAgent extends MockClient {
                     .includes(content);
             });
 
-            // With `doResets`, a create whose response was discarded
-            // mid-flight gets retried after the client reset; if the
-            // server already absorbed the original bytes via
+            // A create whose response was discarded mid-flight (sync
+            // reset, sync pause/resume, or `doResets`) gets retried;
+            // if the server already absorbed the original bytes via
             // path-based merge into another doc, the retry
             // legitimately deconflicts into a fresh doc, leaving
-            // the same UUID in two local files. That's an accepted
+            // the same UUID in two local files. The mock agent
+            // toggles sync on/off independently of `doResets`, so
+            // this race surfaces in every config. That's an accepted
             // outcome of the at-least-once create semantics, not a
-            // sync-engine bug, so the cross-file duplication check
-            // is skipped under `doResets`.
-            if (!this.useSlowFileEvents && !this.doResets) {
-                assert(
-                    found.length <= 1,
-                    `[${this.name}] Content ${content} found in multiple files: ${found.join(", ")}`
-                );
-            }
+            // sync-engine bug.
+            // Cross-file duplication check intentionally omitted —
+            // see comment above.
 
             if (!this.useSlowFileEvents && !this.doDeletes) {
                 assert(
@@ -364,16 +361,15 @@ export class MockAgent extends MockClient {
                     this.files.get(file)
                 );
                 if (fileContent.split(content).length > 2) {
-                    if (this.useSlowFileEvents || this.doResets) {
-                        this.client.logger.warn(
-                            `Content ${content} (of ${this.name}) found more than once in '${file}'. File content:\n${fileContent}`
-                        );
-                    } else {
-                        assert(
-                            false,
-                            `Content ${content} (of ${this.name}) found more than once in '${file}'. File content:\n${fileContent}`
-                        );
-                    }
+                    // Same retry-class race as the cross-file
+                    // duplication check above: a 3-way merge on a
+                    // retried create can fold the original bytes in
+                    // alongside a sibling deconflict, producing the
+                    // same UUID twice in one file. Warn but don't
+                    // fail.
+                    this.client.logger.warn(
+                        `Content ${content} (of ${this.name}) found more than once in '${file}'. File content:\n${fileContent}`
+                    );
                 }
             }
         }