Some surfaces of some props don't collide correctly (GMOD)

[400Ferrets]

cafeteria_table001a is one example I could find (in the gmod Construction Props menu, bottom right)
See attached video, player has no friction on top of table, and sort-of clips up and down on it (server-client disagreement?)
It does not seem to effect props placed on the same table, only the player.
Only the top of the prop has this issue in this scenario.

output.mp4

[YUCLing]

It seems it's related to #3