Tips for Flowmastervalve problem?

I replaced the old-style shutoff assembly in one of my toilets with a Flowmaster kit maybe a yearago (maybe a bit more).
At some point in recent months it developed a problem by which it fills all the way and then does not shut off. Giving the float piece a little tap does shut it off.
Is this a common problem? Any tips for how to address it, short of buying a new shutoff assembly? Was hoping this would be a "forever" solution and save money, rather than the opposite.

My truck has a Flowmaster exhaust system...
My toilet has a Fluidmaster 400A...
If it is adjusted properly and is not shutting off replace it!

Make sure it is not rubbing on anything.