Temporal instability with faces on continuous frames

[2400YrsOldLallo]

--2411

--2412

--2413

I am having an issue when I use GFPGAN for videos. Even though three images are continuous and very identical, the output from GFPGAN for 2412 is quite weird around lip. I assume the issue is related to facexlib since angle of face output from GFPGAN under cmp is different on 2412 compare to 2411 and 2413. This issue leads to flickering-ish experience when its made to video.
I have created same issue in GFPGAN.
Does anyone know how to fix this issue?

Thanks in advance for help :)