Still present in 1.17pre2 (clouds stitches on AMD hardware (event when disabling all anisotropic or other mipmap/post-processing options in driver)
This one is so old I didn't think it was still relevant. But you are right, I can replicate with 1.16.5 w/o optifine, so it is the same pre-existing bug.
The 'nvidia' workaround of disabling Anisotropic filtering doesn't work on AMD.
Just saw this on a 1.19pre4 newly created world: seed -867364958902569562, chest pos 837 60 -256