there is a way to fix that, yes.
Clone all the objects to a new object group, just like this:
instead of MyPlants create an object group named MehPlants
Then go to FeralHeart\media\terrains\yourmapname and open the file yourmapnameObjects.cfg with notepad.
use the "replace" menu and
type this in the "search" box: [MyPlants
type this in the "replace by" box: [MehPlants
replace all, save.
Do that with every object group you want to fix.
and now you should have the map with the objects working again.