As I indicated earlier, GEDCOM does not support a master citation linked to multiple things. FTM exports as many separate citations as you see in that list. It would take some magic to merge them back into one shared master citation but RM's database design does not support it anyway. I see that FTM does do that magic which is one reason its import process is so slow - that is a lot of string comparing to do.
I'm sort of beating a dead horse here. But it seems to me that the fact that GEDCOM does not support a master citation linked to multiple things is not really a barrier to genealogy software supporting a master citation linked to multiple things. Indeed, FTM is already an exemplar of how to do it - simply split the master citation into individual citations on GEDCOM export and merge the identical citations back together into a master citation on GEDCOM import. So RM doesn't have any trouble importing FTM's master citations from GEDCOM because the citations will already have been split in the GEDCOM and RM simply doesn't merge them back together. For direct import of FTM's master citations, I would assume that RM is doing the split as a part of the direct import process, and having split them it once again doesn't merge them back together. RM doesn't merge the identical citations back together because it can't - it doesn't support anything like a master citation.