I have attached some screenshots of the display in Maple 2021 which seem to appear after Maple has been up for an extended period of time (seemingly 3+ hours). The odd characters are not present when the tabs are initially opened, and the problem disappears for awhile after a restart. Generally, I have not noticed a similar problem in Maple 2020. However, the corruption of the output affects not only user created worksheets, but also help pages and examples opened from help as can be seen in the image below.
FYI I am using M2021 on an HP Omen gaming laptop that is several years old, but has been updated (drivers and windows) as they become available.