Torque app reports test fail, no Engine Check Light?

My new-to-me 08 Prius has been running smoothly, except that its mpg is a tad low from pulished specs. I purchased Torque Pro, and ran the Vehicle Test. Off all the items, there is 1 test that is reported as either 'Test incomplete or dependant test failed" Everything else Torque scans for, gets a green check mark.

The test is:

MID: $02 TID:$8b
O2 Bank 1 Sensor 2

Is this a test that applies to a Gen 2 Prius? Woudn't a fail of an O2 sensor tripper a CEL? When I googled this test, didin't find much other than a youtube video of an owner changing a sensor that appeared directly-connected from the catalytic convertor, thru the floor board, to a wire on the the front passenger-side 'hump'.

When I got the car, I did some minor maintenance; tires, air filter, MAS clean, and Torque to scan for faults. This one fail is the only item that Torque reported.

Is this an applicable test, or how do I reference this reported fail to an actual O2 sensor? Could this be a contributor to my 38 MPG? Thank you.