I have reproduced it without driving it:

Start navigation point *before the fork* to go right, set the endpoint somewhere to the east. I've been doing that gas station right off 2200 west. Osmand says to take the right fork, do a U-turn at the merge, and go.

Setting an intermediate destination on the left side of the fork, or setting the start point on the left side of the fork, it knows you can turn left just fine.

I double-checked my navigation settings, and can replicate it with all sorts of different settings