The DMG Aasimar awards a subrace from Volo's while retaining a +1 to wisdom. For example, if I choose a Aasimar I get +2 cha, +1 wis, and then I can choose Fallen Aasimar and get an additional +1 strength. Essentially, if I pick Fallen Aasimar from Volo's I get +2 cha, +1 str. If I pick Fallen Aasimar from the DMG I get +2 cha, +1 str, and +1 wis. The two fixes I can see are (1) that the DMG Aasimar shouldn't award subraces like the DMG or (2) the Aasimar shouldn't get a base +1 wis when selecting from the DMG. Problem pops up on mac, haven't tested it on anything else.