No, it's only when using VRR and the frame rate drops. It's probably not going to be a huge issue, and will only effect grey areas.
Edit:
Update: Yes, we also noticed that with the LG CX you can measure a shift in the gamma curve when using the VRR. But we don’t want to spread panic now, we just want to answer the most important question, if this is bad:
It means that when you are using VRR, areas that are not black but very very dark (near blacks) will appear brighter than they should be. In OLEDs, this is only noticeable because of the almost perfect black level, which remains the same by the way. Nevertheless, LG OLEDs still follow the EOTF curve very closely, even with VRR enabled. Most users won’t notice this little flaw, especially if you aren’t looking for it. If your TV is not professionally calibrated it might even look worse without VRR. By the way, all LCD TVs with VRR look much worse in this regard.
LG CX OLED • 4K TV • HDMI 2.1• 120 Hz • Comparison with Samsung Q80T and LG C9 • Available in 48, 55, 65 & 77 inch
www.tvfindr.com