Mike,
Rebooting Microsoft Edge has no effect on the issues being experienced when using the Microsoft Mail App.
I have not seen any fix and there has been no response from Microsoft.
As I wrote originally, ALL of my mail opened using AOL is perfectly fine, it is only SOME of the mail that is viewed using the Microsoft Mail App that has this issue.
In a wonderfully ironic twist, the emails coming from this question and the related responses, are ALL garbled when using the app, yet here on AOL, no issue at all...