When it comes to online multiplayer, most movement related abilities cause desyncronization between players.
The code is peer2peer, so there's a bug that doesn't handle such abilities well enough, having involved units show up in different places for the 2 players (as online multiplayer code atm is 1vs1 only), ruining the match. Might be related to #1805

Need to confirm if it happens with all movement related abilities or just the ones that modify the location of another unit as well.

Here's a list with some abilities that cause movement for active unit:

• Golden Wyrm's Dragon Flight
• Uncle Fungus' Frogger Jump
• Abolished's Wild Fire
• Gumble's Royal Seal

List of some abilities that modify location of other (allies or enemy) units:

• Nutcases' Fishing Hook
• Scavenger's Escort Service
• Chimera's Battering Ram
• Snow Bunny's Blowing Wind
• Headless' Whip Move (though it's buggy in hotseat Whip Move improper pull [bounty: 66 XTR] #2015 )

Note that in order to fix this bug, you would probably need to have an instance of Nakama server running along with one of the two compatible databases. Here's a set-up guide: https://heroiclabs.com/docs/nakama/getting-started/install/