Okay, so in my case, it turned out to be a problem with >60hz refresh rates. If
I set to 60hz, the problem goes away.

sensors:
amdgpu-pci-0d00
Adapter: PCI adapter
vddgfx:       +0.72 V                                                           
fan1:           0 RPM  (min =    0 RPM, max = 3200 RPM)                         
edge:         +53.0°C  (crit = +118.0°C, hyst = -273.1°C)                       
                       (emerg = +99.0°C)                                        
junction:     +53.0°C  (crit = +99.0°C, hyst = -273.1°C)                        
                       (emerg = +99.0°C)                                        
mem:          +56.0°C  (crit = +99.0°C, hyst = -273.1°C)                        
                       (emerg = +99.0°C)                                        
power1:       12.00 W  (cap = 200.00 W)

cat pp_dpm_mclk:

0: 100Mhz *                                                                     
1: 500Mhz 
2: 625Mhz 
3: 875Mhz

This is a problem on Windows as well, so there looks to be a cross-platform bug
here.

Also, much like Windows, 75hz is even more buggy, with lm-sensors triggering
the weirdness relating to sensor data that some users have reported (N/A
sensors readings, and then a lockup). Windows has a variation of this, with all
sensors being unreadable when using a 75hz refresh rate (but no lockup at
least).

My main refresh rate (92hz) doesn't have the latter problem, at least.