(I'm sorry - I thought I had posted my problem resolution here, but I don't see it now - the discussion must have been in emails between me and Zubersoft...)
For me, the problem seems to have been a timing issue with the SDXC card containing my Mobilesheets database. The card was an older / slower one, from 2014 when I first purchased the device (a SurfacePro tablet running Windows 10). I replaced the card with a newer, higher speed one. It wasn't certain that doing so would resolve the problem (e.g., it wouldn't help if the problem were with the SurfacePro itself and not with the card), but it seems to have done the trick.
My situation / experience may have nothing to do with yours. But, if (1) your misbehaving Android device sometimes displays the symbols correctly but at other times displays the red question marks, (2) the exclamation marks seem to "fix themselves" when you open the music page for edit, and (3) your MobileSheets database is on an SDXC card, perhaps it's the same issue I had.
Good luck - RL
For me, the problem seems to have been a timing issue with the SDXC card containing my Mobilesheets database. The card was an older / slower one, from 2014 when I first purchased the device (a SurfacePro tablet running Windows 10). I replaced the card with a newer, higher speed one. It wasn't certain that doing so would resolve the problem (e.g., it wouldn't help if the problem were with the SurfacePro itself and not with the card), but it seems to have done the trick.
My situation / experience may have nothing to do with yours. But, if (1) your misbehaving Android device sometimes displays the symbols correctly but at other times displays the red question marks, (2) the exclamation marks seem to "fix themselves" when you open the music page for edit, and (3) your MobileSheets database is on an SDXC card, perhaps it's the same issue I had.
Good luck - RL