Hi,
Thanks for your report. Ideally, move XOA VM on another SR than the one doing the maintenance mode. Alternatively, you can do it manually with the CLI or XO Lite.
You raised a valid question: XOA should have detected it was itself on the target SR and prevent it. However, even if it sounds simple, it might not be trivial. Anyway, I'm adding @lsouai-vates in the loop so we can improve this in the future