Have you tried with another keyboard? Wired or wireless keyboard?
I have tried it with a wireless keyboard, no keyboard and have just tested it now with a wired keyboard, still no luck I’m afraid.
Mouse connected? If so, I’d try swapping that out too. Basically, disconnect anything connected except what you need then reconnect one peripheral at a time. Got to admit, this is an odd one if only keyboard is connected.
Yep mouse disconnected too, it’s a weird one. It might have to be one to do a zendesk request with, if all else fails I could do a full reinstall and try again, that fixed a lot of issues/crashes I started getting initially with SU5.
Fortunately if I turn AI rudder assist on it stays straight and makes the sim usable so it’s not the end of the world, I’d just like to have it in my hands and not the AI’s.
Just did one more test. I went through and unassigned every control binding relating to rudder, trim or yaw and cleared them all so in theory nothing external should be able to control it and… same result 
right rudder at 30 knots.
See my post here
This was likely caused by my rudder, but I have solved the issue.