I experience the same issue on 20.04.3 LTS, I think the issue is just lazy pixel updating. When the clock changes numbers, a column (maybe a couple columns) of pixels get stuck in the side of the clock, resulting in a smudge on the side of it. Issue gets resolved by moving the mouse there because it updates the pixels in that area.
I experience the same issue on 20.04.3 LTS, I think the issue is just lazy pixel updating. When the clock changes numbers, a column (maybe a couple columns) of pixels get stuck in the side of the clock, resulting in a smudge on the side of it. Issue gets resolved by moving the mouse there because it updates the pixels in that area.