Yes, I saw what you wrote and tried it with PVE CLI commands to avoid ambiguity of mis-edit. I pasted the commands I used for reproduction, whereas we still dont know if you were properly changing the file (no offence meant).AS I wrote, it just does not work with timeo, setting async does not work either...
I also retried with V4 and my results were the same.
Please take a look at the commands I used and retry your experiment using them on a clean system. If you still can reproduce the problem, report back, including full PVE versioning.
good luck
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