I got a new Samsung S20FE last week and all emails are and have been marked as ‘read’ on this device. I still have my previous Pixel 2XL and this does not happen on it. (Nor on any of the previous half dozen phones I’ve had since 2010 or so.) I’ve done a stare and compare between the 2 devices and see no differences in the feature set up, altho the available features do not match 1-2-1. This happened before going to a Beta release and still happens on 5.724.
DK