I updated to 11.10.5 today and get unexpected optimal route results when "Motor if speed below minimum sailing speed" is checked. This is over a 90 mile course with 5-10kts wind forecast in the grib - I (sadly) expect to motor.

Running a route with with it checked, motor speed of 7kts, and min sailing speed of 7kts results in a 12 hour trip with 00s motoring time. The Mode column in results always says "Sail". Can you check if the results panel is incorporating this motor option correctly?

Other options I tried:
Changing min sailing speed from 7kts to 15 kts increases the delivery time about an hour - suspect it is switching some stretches from SAIL to MOTOR, but not showing that in results.

Unchecking "Motor..." box increases the trip duration by 30% and changes the route from rhumbline to points of sail looking for downwind VMG - what I would expect if we tried to sail.