diff --git a/lib/shared/dm-ops/change-thread-settings-spec.js b/lib/shared/dm-ops/change-thread-settings-spec.js
--- a/lib/shared/dm-ops/change-thread-settings-spec.js
+++ b/lib/shared/dm-ops/change-thread-settings-spec.js
@@ -161,6 +161,7 @@
           threadInfoToUpdate = {
             ...threadInfoToUpdate,
             [fieldName]: threadInfoUpdate[fieldName],
+            // $FlowIgnore[incompatible-indexer]
             timestamps: {
               ...threadInfoToUpdate.timestamps,
               [fieldName]: time,