Dual 506 - Auto arm lift being weird

Had this for a few years now and I still haven't understood this. Auto-start works when I pivot the arm towards the disc, no prob. Auto stop/auto-lift though, is a weird gamble. Sometimes I get a proper auto stop with arm lift and sometimes not, no real rhyme nor reason to it.

I have flipped the plinth over and tried adjusting the eccentric to engage auto lift a little earlier and it's helped. I think most frustratingly it tends to work just fine when I test but when I put an actual disc in and let it run to the end, it'll hit the inner runout groove and do diddly squat, but...only sometimes.

I can't figure this out, has this happened to anybody else with an old 506? Early model with the wood veneer case, still a great table for what I paid for it.

Thx!