@girish thank you, and thanks for confirming the fix ships in Cloudron 10.
Adding one data point for anyone who finds this while still on 9.x: we hit the same crash again on 2026-07-06, on 9.2.0 (a build from before commit 33f3ca3), so it recurs exactly as expected until the v10 upgrade:
tasks: setCompleted - 4900: {"result":null,"error":{"message":"Cannot read properties of null (reading 'sort')","reason":"External Error"},"percent":100}
Same app (Langfuse), same place: the task died at app 31 of 73, so the roughly 40 apps after it were left on the previous snapshot again. The du precondition logged the vanished directories first, this time a delete_tmp_tmp_merge_* variant alongside the usual tmp_merge_* ones, and then readTree threw during the upload.
Until we are on 10 we have excluded the ClickHouse apps from the automatic schedule so a single mid-merge app cannot abort the whole run, and we re-run on the rare miss, which clears it. Glad to confirm the fix here once we upgrade, we have a reliable reproducer under merge load.
