Profit Taker Phase 1 kill counter not updating properly

[MJDooom]

I have now twice had the kill counter for the very first part (clearing the corpus in the cave) fail to update properly.  Both time it happened when I was in public matchmaking queue but was in solo without anyone matched and thus far I haven't seen it happen when I was matched.  In both cases there were an appropriate number of enemies in the cave but the counter didn't update on all kills so I would end up with only 1 or 2 kills counted before the cave was cleared and I couldn't progress any further because it wouldn't trigger the step to find the Quill operative (and kills outside the cave wouldn't count either although I think this is expected).