I grabbed the "Joining the Stormcloaks" mission from Galmar a while back and since it was out by Winterhold and I went ahead and did the College quest line. Well I got to playing more and as time went by I forgot about it, so I decided it was time to beat the game. I get to "Season Unending" and I convinced General Tullius, then I head back to Windhelm and try to convince Ulfric Stormcloak but he says something like "Aren't you supposed to be proving yourself?". Well I try and troubleshoot it and go do the quest, complete it by killing one wraith, and when I go to turn it in to Galmar he says "I don't know how you convinced Ulfric to talk to the Empire. Worst than a waste of time if you ask me." I then try to find Ulfric to see if maybe I turn it into him. He says
WITH NO DIALOG BOX "Well done, now go speak with Galmar, you and him will be going on mission together." I try and speak to him to see if I can bring up a dialog box but no luck. When he said that I checked my journal and nothing was added to either quest, it still shows that I need to convince Ulfric, and that I killed one wraith as a test for joining the Stormcloaks. After that I ran to Galmar again and he said the same thing as before "I don't know how you convinced Ulfric to talk to the Empire." But I haven't convinced him to talk to the Empire, or me for christ sake..
I know this was a tad long but I feel as though most bug/error reports submitted by most users, isn't detailed enough. I hope this helps, and/or gets fixed in the next patch. If anyone has tried anything else or has the same problem please comment below or explain what happened to yours.
Thank you.