LR or CR profile correction and/or crop tool seem to cause a grid artifact in PS using channels

I am getting a grid artifact when using channels to create selections/masks in PS. My process is to duplicate a channel and then adjust it with levels.

These seem to be a result of applying either or both the lens profile correction and a crop in LR or CR.

Spot checking a few images, this happens to images that have been imported since upgrading adobe products recently (I am always behind...). For example if I edit a Milky Way photo from 2018 with the same camera and lens set up, same versions of LR and PS, there is no grid artifact.

Other things to note:

Applying a lens correction in PS does not lead to the grid artifact.

I checked this on images from different bodies and lenses, even different brands.