Why do my images get corrupted when saving from PS to LRC?

Is this every image or just some?

Do you have an external drive that you can test with, if you are using the main drive in the laptop?

Not a direct answer, but you could try a 2-step approach... With the image from Lr opened, do your regular SAVE so that it automatically updates back in Lr. While the edited image is still open in Photoshop, do a SAVE AS/SAVE A COPY and save a backup file that isn't in the Lr catalogue to preserve the edits from Photoshop, just in case the first step corrupts. This can be automated if it becomes a bother.

Good luck!

Yes, that looks like file corruption and not a GPU failure - the histogram here doesn't look very promising either.

File corruption is always caused by failing hardware. You need to isolate and replace the failing component. Try to make a note of exactly when/where in the chain it happens.

If you save directly to an external drive, that's a prime suspect. Maybe not the drive itself, but worn/loose cables and connectors. External drives get kicked around a lot. Start by replacing all cables.

To be clear, Photoshop doesn't save "to Lightroom". It just saves to disk. So if it's corrupt when saved from Photoshop, that points to a disk failure.