Same for me :
ACER Aspire A315-21 AMD® A9-9420 radeon r5, 5 compute cores 2c+3g × 2 AMD® Stoney Ubuntu 20.04.3 LTS kernel 5.11.0.41 to 46
Edit : Solved by the update to the 5.13.0-28-generic kernel
Same for me :
ACER Aspire A315-21
AMD® A9-9420 radeon r5, 5 compute cores 2c+3g × 2
AMD® Stoney
Ubuntu 20.04.3 LTS
kernel 5.11.0.41 to 46
Edit : Solved by the update to the 5.13.0-28-generic kernel