Odd behavior of tonearm on Pioneer PL15D ii

This is an odd issue that crops up every so often with my Pioneer PL15D ii.

When cueing up to play a record, sometimes the stylus will hit the lead-in groove and then swing out and off the record. (I'm using a Realistic/Shure RXP3 with the EVG nude N92 stylus). Doesn't do this every time. And the behavior will last for a week or so and then not do it again for a year or so. The last time it did it, the table had just come back from a refurbishment. The guy working on it suggested cleaning the rubber along the cue lifter that the arm slides across when raised and cueing or when cycling at the end of a side. That worked.

Doesn't seem to be working as well this time. I've checked the table for level. It is. I've also checked the anti-skating and that seems to be working just fine. I'm tracking the cart at 1.4 grams. When lifting the stylus during play and then dropping it again, it comes back within a groove or two.

So far, no damage, but I'd like to put a stop to this. Any suggestions?? I'm baffled.