When saving a map, data is lost.

I encountered a similar problem. When saving an edited map, a warning message appears: "as you've changed this map, rmg marker will be lost and multiplayer regeneration won't work," and the RMGmap trigger is set to false. When I change it to true and save the map, the same thing happens - an error message appears, and RMGmap is set to false.
Saved maps can be edited, but they cannot be launched.

Path to the game folder: C:\HoMMVHE\Heroes of Might and Magic V - Tribes of the East
Map name in English.