Indeed, and one that has not really been answered by the team. It just stops as you have found.
No, that is exactly the way Bubble is currently working. You cannot rely on workflows completing.
It appears to be an issue with record contention (what we used to call a “two dogs” situation back in the DB2 days) not being handled.
I have seen this several times when you want to create x things and update a particular thing to add each one to the list.
As above, moving to an API workflow is the answer, but it fundamentally won’t cure the issue. What you need to do is space the API workflows out sufficiently to prevent contention. A few seconds should do the trick.
It is on the Roadmap to be fixed, and that can’t come soon enough.
This …
…looks like it might be the start of it 