Whenever you update an inactive plugin, Studio will behave as though it is active despite never turning on.
Of course, the expected behavior is that it will update but not suddenly run its code when you didn’t want it to (supposedly for later use when you do wish to turn it on). Happens 100% of the time.
Video example:
I’m unsure when exactly this started, though I believe it’s around the time when plugins received an update that allowed them to refresh individually instead of doing all of them at once.
Simply turning it on and off again will fix it, and restarting Studio will treat it as though the plugin also never turned on.