Upstream has released updates that appear to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing
CraftBukkit Changes:
f92c94517 SPIGOT-7310: PlayerToggleSneakEvent is not called when a player sneaks while riding an entity
b5714184d SPIGOT-7316: Cancelling EntityUnmountEvent does not stop the all effects of the unmounting
e237f8c88 SPIGOT-7312: Entity#setVisibleByDefault on player causes skin reset on this player client