Finder red, yellow, green buttons need two clicks to activate?

I’ve recently found that any Finder window needs two clicks to activate one of the red, yellow or green buttons (top left in any Finder window).

So when I want to minimise the window and I click the yellow button, it goes darker and then I have to click again to minimise. This occurs on all three red, yellow and green buttons in the Finder window. It only occurs in Finder not any other app.

CleanShot 2022-10-10 at 09.27.19

Have I inadvertently switched on some accessibility function, and if so, how to I return the behaviour to a single click?

Do you have something like BetterTouchTool? With BTT you can hijack the clicks on those buttons to perform custom actions (and there are nice extensions, BTW).

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Have you tried to reboot? I feel like this would happen if the Mac thought some vague modifier key was constantly pressed.