I bought a stern pirates last year that has the same ribbing. The machine is from 2006. Playfield is beautiful otherwise with not even a dimple. Then I bought a nib guardians that had the exact same thing. Looked identical as if the same machine sprayed the playfield. My distributor said it sometimes happens and stern won't warranty that but I never tried to contact them. Interested to hear what they say to you.

There is a Godzilla premium on route around here that has way worse ribbing than that one. I've never seen the ribbing so bad. Funny thing was the pro that was sitting next to it was smooth as glass.

My guardians had it pretty bad as well. Similar to yours and my distributor said it was normal and stern would do nothing about it. My avengers premium that arrived in Sept didn't originally have any ribbing as I checked it close but has developed very minor ribbing as the air got dryer the last few months

There are a number of new machines on location around here and every single one of them has some level of the ribbing. 2 Avengers Pre that I've seen, Rush Pre and a Pro, Godzilla pre. The worst one I have seen is the godzilla premium. Most of them you have to really look for it.

Congratulations, My distributor told me to go away lol. Glad you got a good resolution. I am a bit shocked they warrantied that with a fully populated playfield. Chips in the playfield on my AIQ Premium only got me an unpopulated playfield I'll have to swap over at some point. Not looking forward to that.

Check back in a few weeks. My aiq premium arrived last September with a nice glossy finish. It looked perfect. I couldn't find a flaw anywhere. After 3 months ribbing started to apear. I keep the house at 35-40% humidity year round.