Chosen Solution
I’m currently using a 2016 MacBook Pro Touch Bar. Because of the Apple repair program for sticky keys, I just got it back and opened it. It is originally a 2016 MacBook Pro but with the sticky keys repair, the top case was changed to the 2018 model. After I got it back(originally there was no problem) but the brightness and volume sliders don’t open up when I press them in the control panel. Any suggestions?
Apple is replacing the uppercases on many. It sounds like you got a double whammy! The Touch Bard is bad! As this is a defective part you’ll need to bring the system back to get it fixed under the parts warranty. I would got back ASAP as the longer you wait the less likely they will honor it.
