Sorry if the thread name isnt really clear, and i pointed the newest version but i noticed it on the r109 too.
The issue is that sometimes, the object using the platform behavior after landing, it will go a pixel inside the solids.
Heres some screenshots, one from my own project i started a few hours ago
And two from a game from the arcade which i forgot the name now (sorry )
On the first image you can see his little feet is perfectly aligned with the grass pixels, but on the second one it goes a pixel down into the grass.
Heres the capx
and an exported link
Tested on Rockmelt (which is pretty much Chrome) and Firefox, Windows 7, NVidia Geforce 9800 gt