I doubt it depends on the monitor tbh, I have an AOC AG241QX and freesync NEVER worked to me. On GTA it does reduce the tearing but not delete it, on Crysis freesync only works in windowed mode ( Take a look here please), while in other games it won't work in any way.
Maybe something changed in the recent drivers in the way it handles Freesync and older monitors implementation of the tech is now outdated for it to work properly?
I have created a ticket with engineering and they are looking into it. The problem is we don't have very many reports, just a few users with this monitor, and i myself have not been able to reproduce the issue despite having the same monitor and graphics card. I'll update the thread if and when i have anything to share.
Thanks but no need, we are already looking at the issue and do not require any further DXDIAG reports or demonstrations of the issue.