A player sprite on a vertical moving platform is "shaked" with "Bounding Box" Collision on both the platform and the player. This is the 1st bug.
I tried to Use "Per Pixel" on the player, but the player fall trough the platform. This is the 2nd bug.
I I use "per Pixel" on the platform and "Bounding Box" on the player, the bug is fixed.
See .cap to see the bug in action.