I'm having issues with some images - The image edits fine using my normal B&W preset in Lightroom Classic (All up to date), and exports fine so the RAW files seem to be ok, but when I sharpen them (in my normal way in PS, using a preset I've always used for years), these coloured errors come up on some of the images. It only seems to happen on B&W images though, and not all of them.....
I've tried re-exporting the problem images and then sharpening them again, and the same thing happens.
First, try disabling GPU in the Preferences (Performance tab). Any better? If not, recalibrate and build a new ICC display profile, the old one might be corrupted. If you are using software/hardware for this task, be sure the software is set to build a matrix not LUT profile, Version 2 not Version 4 profile.
If turning OFF GPU works, it's a GPU bug and you need to contact the manufacturer or find out if there's an updated driver for it. On the Mac, that's part of the OS update(s) so if this is the latest OS version, you may need to roll back a release. Also see: https://helpx.adobe.com/photoshop/kb/acr-gpu-faq.html
Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"