I noticed this too when I floated it last week. After this years sustained high flows the main channel has shifted to the left under that downed cottonwood. It used to go right, but now goes mostly left... I'm thinking about floating this section tomorrow with a chainsaw to clear up that strainer as it is quite dangerous, and as the water drops more and more the old right channel may become too narrow to pass. It was already pretty narrow last week when it was still running 1900cfs. I barely got by in my 14ft raft.
It is fairly obvious as you are floating down, you should be able to see that the main channel goes left and that cottonwood strainer makes it impassible. You will see that there is a small channel to the right but like I said it is narrow and there are some pointy looking stumps on the left bank that could pop your boat if you were forced to run into them. My suggestion is that as soon as you see the downed cottonwood river-left, pull over river-right and walk your boat along the bank passed this tricky section, just to be safe.
I am planning to float this tomorrow with my gf from Willits around 8am with a chainsaw to clean this up... I do believe it will become impassible once the water drops below 1000. If anyone wants to join, I'm sure I can use an extra hand... Let me know... or if anyone wants to go on a mission this afternoon I'm down... of coarse I will be bringing my fishing pole too