Multiplayer custom map loading crash on 2+ players

Hi there!

1. I make a map in editor or download it from steam workshop.
2. Create a multiplayer game (local lan) and invite my wife.
3. Ready and play > loading bar goes to the full.
4. I enter game but wife gets a crash.
5. She reloads game and we repeat 1,2,3
6. Bar loads and we play no problem.
7. Sharing the map is successful as she has it in her steam profile afterwards.
8. Happens with every map we tried.

Skirmish has no problems.

I believe is a map sharing issue on first try, the game does not finish the whole transition or starts the map when is incomplete (wild guess).