Hello guys!
First of all sorry for my english, but I think I find a method go to the next season without change the team and hopefully help you.
My steps:
1. Striker at Rapid Bucuresti (Romania) - season 2 overall (second season at Rapid and on first season I was at Salford CIty, Leaguea 4 in England).
2. I have same issue as many of yours - I mean I have al mandatory objective accomplished but one the optional objective is not achieved - So ... At the end of the season don't appear the button "Renew the contract" (check first image).
3. Lucky1 me/us - there is an autosave.
4. My last match was on 10 Juni (doesn't matter).
5. Go Advance, BUT Between 25 and 29 JUNI you must Stop the sim
6. Here is the tricky one 🙂) Go to customise and select another role (the one who accomplished all objective). Lucky2: For my case was a central defender who achieved all objective (mandatory + optional).
7. At the end of the season the button "Renew the contract" appear :D - check the second image.
8. So now, I am starting 3th season overall and 2nd season at Rapid Bucuresti.
PS. Yesterday my head encountered same problem and I was searching a method for 24 hours, I have a headache but I'm happy I resolve 🙂) Hope you find this useful 🙂