Much thanks @bastereo. The nut and/or the plastic collar is the issue I believe. The glass fits loosely on the plastic collar and with any use slides off. I don't believe I have a nut in place or it is not tight enough to expand the plastic collar.

I had checked real oem but was not confident with my reading of the schematic (or maybe I was looking at the wrong one).

I'll post the results. Again, much thanks.