I noticed while running the test added via SPEC-1214 that mongoc seemed to still attempt resuming - using command monitoring I saw the following order of events:
- successful aggregate
- a successful insert
- a failed getMore
- a successful killCursors
- a failed aggregate
Looking at mongoc-change-stream.c, I believe this is because the code here checks for "NonRetryableChangeStreamError" rather than "NonResumableChangeStreamError".
I think this mistake occurred because the original commit for SPEC-1214 wrongly used "retryable" in the .rst file. This was corrected in a subsequent commit under the same ticket number.