I seem to recall looking this up over a decade ago when I got this gun, but noticed it again today cleaning it up. It looks like the very thin polymer on the front rail horseshoe has broken off in two spots. I think one of them was from the factory, but it's been so long I don't remember. Normal for a gen 4?

I broke one on both a poly 80 and a printed frame from being Dremel happy, both run fine. See what happens when you clean guns op?

It can be normal. I’ve seen some have it and some don’t. I would monitor and see if it progresses. It likely will not.