I see. Then the problem is not the files, but the apps and your having moved things is the cause. It must be a problem with the app(s) in question. Since I don't know what app(s) or file types, I can't answer at all on that, however you may have to move them back to the tablet itself to remove the problem, since the app(s) may not be able to alter them while they are on the SD card.
It may also be the update that was installed altered the app(s) changing the permissions. That happens a lot.
In such a case I would suggest contacting the creator of the app(s) and asking them if the move is why, if the update made the permissions change or if there is something else going on with it/them.