Discussions are not presented for MR diffs (race condition with diffs batch load)
There's one scenario with diffs_batch_load feature flag on that doesn't load the discussions (even though it shows there are unresolved discussions):
It only happens when the discussions.json responds faster than the diffs_batch.json request:
Note that the request order is right, but that's not enough to avoid the issue, given the discussions.json can respond faster. I had to give it a few reloads in order to reproduce the bug.
Important: The same bug happens if we open the MR (Overview tab), then click the Changes tab.
That's a blocker to enable the diffs batch loading at GitLab.com
Edited by Oswaldo Ferreira