(season unending spoiiler.)

I've played 200 hours without doing neither the main quest or civil war quests, so please avoid mentioning any spoilers in comments.

I started Season Unending quest while I was still on Jagged Crown quest. I found the crown, but haven't decided whom to give the crown to(I've joined Stormcloak). Upon General Taliu's first offer of turning the Rift to the empire, I was given two options of advice to give to Ulfric, the first being trading Rift with Morthal and second being the Reach.

Either choices result in Ulfric standing up and expressing his doubt about my Loyalty.

Why should be I despised by Ulfric for giving him the term that he wants(the reach)? The negotiation precceeds but Ulfric keeps mentioning he is disappointed by my judgement when I've done nothing against Stormcloaks.

What should I do to fix this problem? I know I could continue playing, but for immersion I want Ulfric to behave plausible.

Ulfric and Galmar both believe that if you aren't 100% on their side, you are against them. If you don't settle the war for one side or the other, neither side is particularly thrilled with you.

I've never played through Season Unending. I always end the war by siding with one side or the other.

Interesting. Did you kick Elenwen out of the proceedings, or let her stay? If you did kick her out, then I'd say jump ship to the Empire.