Task view / Alt Tab previews often disappear after long idle / sleep / hibernate and are replaced by icons of the apps instead

extremely frustrating issue , i then have to manually click every open program/browser window again to regenerate the thumbnail/preview...
Like VLC and Explorer in the (win10 but it's the exact same) screenshot below but every single window is like that.
any idea ?

Bonus question : Spotify and Discord seem to very frequently switch to a black preview on alt tab and task view...some say it's related to chromium/electron but not sure..

Thanks.