Hi @Lexakb and welcome (back) to the community! I am sorry that this will not be a very optimistic first reply to your bug report, but it will if nothing else, be an honest one. But at this point in time, Funcom has not acknowledged any bug reports in >2 months now. I personally have run afoul of this issue in the past first-hand, but even when the issue was at its peak, and dozens of reports were made concerning the issue, it was never officially acknowledged and there has been no targetted fix for it. In fact some of my friends may still be affected by it. @LostBrythunian did your Singleplayer game ever remedy itself? I am deeply sorry, but the best I can offer you this day is a link to my thread at the time, which contained a list very basic recommendations.
Hopefully one of them will do the trick, or another members own experiences may provide some ideas. Try them. But PLEASE let us know how you went. Alsohe next update comes out “later this month”, so if all else fails, try to fire it up then. You never know.