So, if I have this correct:
1. Assign a keyword to an image.
2. Create a virtual copy.
3. Filter for the keyword (both images appear)
4. Select the virtual copy.
5. Edit in Photoshop - Quit Photoshop save
6. Edited version of virtual copy does not appear in filter list.
7. Go to folder where original resides, Original and the virtual copy edit are present and the virtual copy has the keyword.
8. Return to filter from step 3 - virtual copy edit still not present.
9. Restart Lightroom and return to step 8 and virtual copy edit is now present?
If instead of going from 7 to 8, you went to a different, unrelated filter and then went to step 8, is it there now?