Not here. What operating system? Any chance you are editing smart previews and the master images are located on an external hard drive that is disconnected? In that particular situation, Lightroom Classic will not send those smart previews to Photoshop.
1) The photo is 'missing'. Lightroom does not know where the original photo is stored- it has been deleted, renamed, moved, by the OS outside of Lr. Grid view thumbnail is showing a [!] on the border? (or possibly a corrupt file)
2) You are using Smart Previews and the original file is not connected to the computer or available to Lightroom. (eg. external usb drive not connected). Plug in the external drive- check that it is using the same Name/Letter as before. (Also see the link for Missing photos)
3) Lightroom and Photoshop are not linked correctly in Registry/plist. See this link-
The Link above doesn't solve the problem. I noticed the same bug since LR 9.3 MAC, not ob Win10. Meanwhile I uninstalled PS to a former version: no sucess. CMD E works no longer. Thanks for some needful help. PS defaults in LR all grey 😞
It is me again. Now I've deinstalled PS an LR-C. On MAC there is no new situation. WIN 10 runs perfect from the beginning since updating to LR-C 9.3. Deleting com.adobe.Photoshop.plist was no suitable medium, unfortunately.