Edit: I don't know if the original post was edited or I just didn't see it before, I see you found bad parts in the supply,
so my reply below doesn't apply, but is still good for other situations.
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I'm not sure if you originally had a link in your reply ? It's possible there's a defect in the board, but if you haven't already, I don't know if you can in its current state because you said buttons aren't working, but the best thing to do when things are acting strange on any unit with no solution, is to do a factory reset. If it's still acting up, at least you know it wasn't a setting or programming issue. It's possible yours might end up being a loose cable inside or something defective.
I did a quick Google search for resetting the Behringer X32 mixer
[URL unfurl="true"]https://www.sweetwater.com/sweetcare/articles/how-do-i-restore-my-behringer-x32-to-factory-settings/[/URL]
