I’ve had this problem many a time, I like to redo players careers, for example I did Zlatan’s career where I started at Malmö as the manager with the zlatan created pro in the squad and then took managerial jobs based on the club he played for next, I released the pro I made of him each time, then signed him on a free. I’m doing one at the minute with a created pro and this kept happening, I tried playing around with saves and stuff to counter the bug and got this method.
Make a save.
Then change one of your team sheets, which over rights the auto save, then back out using auto save and quit.
Then go to settings - profile - delete, then delete the auto save you just made.
Go back to career mode using load career mode and load the save you initially made.
Then go to save game, delete that save and make a new one
Advance to next season and the player should be there
I’ve done a lot of trial and error with this and this way seems to work, I started by just randomly deleting saves and making new ones and stuff like that until I landed on this method