First match of the year yesterday, and my MKII failed to cycle consistently.

Tried multiple mags and randomly it would fail to load/feed because the bolt creased the center of the top/next round in the mag.

I know this is a simple cause and fix, but what do you suggest?

Thanks!

1) Clean and lube your pistol.  And chamber. And magazines.
2) polish your feed ramp
3) Use good quality ammo that will cycle the bolt (CCI Mini Mags work well)

Start there

I had one MkII that had been dissembled so many times (barrel off the frame) it was no longer tight. Not mine [working gunsmith w' FFL]
The barrel had a tiny amount of rotational play and the hammer dragged on the bolt slot after a few shots.

Back to Ruger for that fix.

Check your extractor, mine broke once and did the same thing.

Have you tried spraying everything liberally with Breakfree lube. I used to lube the loaded mags and hose the inside of the gun with it.  Really helped with reliability

Ruger Mk series .22's are very reliable as a rule. I have done minor work to them like polishing the sear and feed ramp. I've has problems getting one to stay locked open after the last shot, I shortened the bolt lock spring a little and it works fine now.

Some .22's (any brand) can be ammo peculiar. Having a definite preference or dislike for certain brands. If a good cleaning doesn't work try some other ammo. Virtually all Ruger .22 pistols will work fine with hi velocity .22 ammo. Sometimes I have problems with low velocity target ammo that is only traveling around 1050 to 1080 fps.

Mine doesn't like being dirty. When its starts acting funny, I need to strip it down, pull the grips, pull the bolt and hose evrything out with cleaner.

Keep it clean and use full power ammo. Mine hates anything but the strongest ammo. When it gets dirty and the bolt slows down or if I use underpowered loads, I get the same dents in the round on the top of the mag.