Magicians bosses reveal why most important character couldn't return for the finale
https://www.digitalspy.com/tv/ustv/a32051916/magicians-quentin-coldwater-jason-ralph-finale/
Sounds like BS for me
Except that that explanation doesn't make any sense.
When Penny died, there was only more of him on the show, he never disappeared.
There is obviously a different situation with the actor in this case, whatever that situation happens to be.