Hey @Froldev
Gut feeling says the issue has to do with item linking and generally that nested loops don’t behave exactly as you’d expect compared to code.
Item linking
Try returning only one item on the return path from the second loop node to the first loop node. Usually when you return more than the batch size, the loop node will treat the unexpected new items and it’ll try to loop again. A solution is to use the aggregate node in between them to ensure only 1 item is returned.
See docs here - item linking
Use a Subworkflow Instead!
Alternatively, consider using a subworkflow (“Execute another workflow” node) instead of a second loop. Separating the executions avoids most item linking issues but again, ensure you’re not returning more items than necessary.