Sometimes it happens that a player joins the game while a new one is being created, but they are not visible (there is no standard message saying "Player has joined the game"), and messages either don't arrive or have an unclear delay even after troubleshooting.
There was also a case where I couldn't join the game because of a firewall block (from the opponent's router). I didn't believe this could happen since the connection in the game worked without mods. So, it seems like another process is created, but it doesn't appear in the task manager, or somehow Heroes3.exe is modified?
And again, an old bug appeared. In the picture for Luna, the secondary skill Luck is displayed, but the tooltip says Ballistics. And actually, it's Intelligence: D
I am also attaching the save file