Similar problem. AUX buttons don't respond, and after the BL touch sets the table height it lowers it to 25mm below the nozzle, so I can't make any fine adjustments.

Perhaps I am doing something wrong, but I don't know what.

I'd be very grateful if anyone could help with this? 

Check your firmware version.  I bought the Ender 5 Plus and silent board bundle and they sent the silent board two weeks after the printer.  Now that I put the "new" board in I'm having the same problem with the aux level buttons not registering or registering like a minute after I press it and then the board just going up and down over and over.  I checked the firmware and it's older than the one that was on the "older" board the printer came with.

Same here. Using lates firmware 1.0.4.9 

Any news about the problem would be fantastic. 

Please try the latest version firmware. ? 

https://forums.creality3dofficial.com/download/ender-series/ender-5-plus/

@kevin i have the latest 1.70.2 on a new machine and I have the same issues. has there been a fix??

@dbrinas Ender 5 plus? What is the mainboard version? This is the firmware issue, flash the latest one.