@ci Well, I'm human, so there could definitely be a bug. 😅 It's just implausible as plug-ins don't come with that kind of power. Plug-ins can't overwrite or delete files from other plug-ins or themes.
They can overload files, however. That is to tell the system, "hey, use my style.css instead of the original one". That doesn't touch the original file, though. It's still there and comes back as soon as you uninstall the plug-in.
My plug-in doesn't ship a style.css. In fact, it comes with 0 % CSS. 😊 So I think something else caused you loosing that CSS, but I would like to make sure that's the case.
Where is your CSS file located? Have you created a custom theme?
Do you have any theories, @manton?