Can anyone with R3 version of the game help to check the product code? Copy your save file to USB, plug into a PC and check the folder. It should be something like PS4>SAVEDATA>xxxxxxxxxxxxxxxx>CUSAxxxxx. Ignore that long string of random chars (xxxxx...), that's a code representing your account. We are interested in the last part. (The R3 game case cover or the game disc itself may show a different product code, like PCAS-02031, but it's not as accurate as looking at the save file.)
The R1 version is CUSA-01633, R2 is CUSA-01615, Japan is CUSA-01570/PLJM-84059/PLJM-84060. I am wondering if R3 matches any of those. If it does, it could mean DLCs are cross-region compatible between R3 and that region.