Ridiculous amount of runout grooves in deadwax/matrix, has anyone seen this?

I just found a super clean copy of Cass Mccombs/Big Wheel And Others. Awesome album, played great, but when I got to literally the last groove on side D it started to repeat the groove. I’ve dealt with this before, so I turned my anti skate off to see if that was the problem, still repeated. Checked under a bright light, didn’t see anything, gave it a light cleaning, still repeated. So I put some pressure down on the tonearm with a finger, carefully, and got through to the deadwax. But it wouldn’t runout, and to my surprise when I looked at it under light, it had to have had 50-60 grooves, maybe more! I’ve never seen anything like it, has anyone else seen anything like this?