That is an odd one sausagematty, I checked there just now and not seeing anything like this on my end or other reports of it.
Wondering if it may be a corrupt save or something along those lines.
When the issue pops up, do you see an error message of any kind? These can provide info that points in the right direction to getting a fix.
Has it been ongoing for some time or just recently? If new, then it is well worth closing out of the game fully and then loading back in to see if it makes a difference.
Let me know how you get on and I'll do what I can for you.
Darko