I bought WTBurnette's spare 40P off of him, with his full disclosure of the cycling issue. On my first outing with it, I ran one of the 10 round mags with the original spring and one with a Wolff extra power spring. The extra power spring ran well through 25 rounds and the standard mag had multiple issues as he had experienced. On the next outing, I ran 50 rounds with only the extra power sprung mag and again, had issues, but not as many. I think the fresh springs helped, but did not completely eliminate the issue.
The next thing I tried was to use the mold ejector pin guide rod and it's been perfect since then. I've run 150 rounds through the gun in two range sessions. The first was just 50 rounds at a moderate pace, so I never really did warm the gun up much, but this mornings range trip saw 100 rounds run through the gun in about 10 minutes. That warmed the gun up a lot and the gun still worked perfectly. I'm going to put a fresh, factory recoil spring in the gun just because I don't know the round count on this, but I'm confident that the issue is gone now. My guess is that the plastic guide rod just was not up to the task of controlling the spring and especially when warm, allowed the spring to contact the barrel when the gun cycled. That's my theory at least.
After 150 rounds, I see no problems with the steel pin wearing on the frame. I'll be keeping an eye on that though, but don't think it will be an issue.