Are you running any 3rd party tools that might be causing this? A user had a similar problem over a year ago, turns out it was the "Better Snap Tool."
Small interface glitch with the column dialog (RB 6.5, Catalina 10.15.7)
When right clicking in the columns header in order to display which columns i get displayed there, the overlay often just flashes and disappear immediately. It's a matter of luck how often you have to do it until it stays.
Screen recording here:
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Forgot to reply here, thanks, it was indeed caused by "Better Snap Tool".