No. it's the first DLC I install for that game and I made sure to check everything with Savedatafiler anyway.
More than that, it works with the rom but not with the cia, both being the same game, same ID, same everything pretty much.
That's why it's strange
The only thing I can guess is converting it to CIA changes it somehow (perhaps different md5, header is modified, it "trims" it) or similar, and therefore makes it not compatible with DLC from the other copy of the same game. I'm honestly not sure.
If the DLC doesn't work then there's definitely something wrong with the CIA conversion.it doesn't
just an update to the situation. it seems region free cia games aren't compatible with DLC.
however DLC work fine with cia games that aren't modified to be region free