The blue tile you're using in your demo is pushing the mob one tile to the west the instant it's stepped on. When you walk onto it moving north, instead of gliding north you'll be gliding northwest onto the new tile. The diagonal glide means your mob is still considered part of the nearer tile for layering purposes until it reaches its destination, as is explained in the Reference.

To avoid any graphical anomalies you'll need to make the blue tile push your mob over after the original glide onto the blue tile is completed. The easiest way to do this is to put in a short sleep() and then test if the mob is still standing there.

(Also, I highly recommend posting files to your member file space instead of mediafire. Files are much easier to download when not going through one of those ad-riddled services.)

I see what you mean there. That is a legitimate bug (and not necessarily an easy fix). Please post it in a separate report.