I have exactly the same problem on my brand new 888, same channel input !
Unfortunately it wasn't a Firmware issue .
After a communication with SD, they asked me to send the device for
repair plus I have to pay for the shipping costs for a device that is being used just for a couple of months until I realize the problem.
Totally unfair, unpleasant and frustrating .
Still on the way for repair.
And now I am relying again on my old like a dinosaur, but still trusty backup 633.