This is very confusing. How can it be a permission error when the game can read and write files without any problems.
It has no problem reading a save file that the game created but it doesn't do that for the old save files. I think it's either a version compatibility issue or just android being buggy.
So, unsure if you figured out the issue, but in some cases when you go to update a renpy game in mobile it can have some weird errors take place. My best example from experience is when I downloaded an update for a different game that refused to update the game, then the next update just installed a completely new game file (basically duplicating the game files with a new one) and the new one couldn't grab the save of the old file. Had to just start over entirely as well, because the save files were incompatible.
I bring up this example not as a "this is how you fix it" but a "I hope it isn't this bad for you" example of how fucky these games can be on Android ._.
