Saw a post about the same exact thing, found the same work around as the previous post (link:https://community.amd.com/t5/drivers-software/7900xt-issues-with-mouse-on-2nd-monitor-in-portrait/m-... but wondering if there is any permenent solution on the topic. Not have to turn on display pointer trail to actually be able to use amd graphics card in portrait mode. Thanks for the respons!
Just do a clean install, for me worked perfectly.
i have this problem upgrading from a 3070ti.
ddu doesn't work that well i guess