Hello,
I noticed this with a recent Samsung update so possibly other android OS will have this as well.
I believe it is due to the accessibility settings for Bitwarden and the pop-up overlay on mobile.
You can disable this within the accessibility settings of your phone under accessibility button, and turn off the app for Bitwarden. This will still leave the pop-up overlay if you use that 
Absolutely bugged me so much after the initial update until I figured out to disable it. Didn’t realize I also had some family members who suffered with the annoyance for several months before they asked how to remove the pop-up button as well. 