Update: I input a versions of the embed codes for multiple videos in phpmyadmin and it worked!
Thanks for the insights George. I think it might be a break in the Morpheus theme. I had tried deactivating all of my plugins (except one, which was added after the problem began anyway), but it didn’t fix the problem. Do you think that maybe I’d be able to go right into phpMyAdmin and put that embed in there in the same place and format that it is in the other portfolio posts?