loop stops executing

I have a loop within a workflow, several of them, that have been working for more than a year but one of them just stops after one iteration. No error, no message, just stops.

The end node becomes yellows as waiting to star executing but doesn’t execute further.

The end node stays in queued for some time and them becomes yellow.

Whn I isoleted this loop, it works.

The end end node has no dependencies nor do the nodes inside the loop (any external connections)

What am I missing?