did you let Thane bind with Fia or cure him with a potion? If you’re stuck, the love and relationship guide should be able to help you
hmm I will try to explain the best to my abilities, but apologies if it’s hard to understand.
Basically there a lot of prequisites to get Thane. First you have to complete the Find the Culprit Quest before Meyza ask you to meet a second time. You can do so by checking the doodles on Winston’s desk and submitting the quest. Then when Thane bit Fia, agree to go and accompany him to see her. Then do not craft the cure and instead just wait until Io’s arc is done, once you inserted Io’s heart, Thane should ask you to bond, say yes.
i have many players and patrons finishing with Thane so I don’t think it’s a coding issue, but let me know.