I had the problem with Skyrim SE in 2021. This solution worked for me: However, after I travelled to the Stormcloak camp, I had to walk to Whiterun and enter the city for the bug to be fixed. Once I entered the city, the situation seemed to be back to normal (people in the streets, icons on the map) and Ulfric could be reported to. Note: I have the unofficial patch mod; not sure it makes a difference.