I get the same error about EDID contradicting itself with older driver versions also and refresh rate changing works with those.
And I did try new drivers with setting UseEDID to false and setting modelines by hand with these values:
HorizSync 14.0 - 70.0
VertRefresh 23.0 - 62.0
ModeLine "1920x1080@50p" 148.50 1920 2448 2492 2640 1080 1084 1089 1125 +hsync +vsync
ModeLine "1920x1080@24p" 74.16 1920 2558 2602 2750 1080 1084 1089 1125 +hsync +vsync
ModeLine "1920x1080@60p" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
The whole xorg.conf is in there with the bug report. Modeline settings are commented out but I have tried them.
With manual modelines or using EDID xranrd displays correct options, 50Hz, 60Hz and 24Hz, for refresh rates just the changing doesn't work.
When trying to change refresh rate the screen goes blank for a second as it usually does but rate is not changed. Both xrandr and nvidia-settings show the old refresh rate still.
I'm happy to try different xorg.conf settings, though. Are newer driver versions more picky about edid or someting?