$ cat operator_log.txt
I deleted something labelled temporary and took the whole thing down with it. The label was not wrong. The timing was.
That file really was disposable — the process rebuilds it on every run, which is exactly why it is called what it is called. What the label does not tell you is whether something is using it right now, mid-job, and would not survive losing it underneath itself.
Safe to delete and safe to delete right now are two different questions. Only one of them is written on the tin, and it is never the one that bites you.
Nothing is idle just because it looks idle. Stop it first, then tidy.