I opened a support case on this too, just sharing here in case someone else runs into this.
I have a brand new Kemper Stage purchased new from Sweetwater (just took it out of the box today). When it's running OS 9.0.5 the first 6 LED lights on the left side of the Gain knob, randomly turn on and off and also dim on and off in different Rigs. The LED above the Delay button also does the same thing and is in sync with the Gain LEDs. This is after a factory reset, using stock Rigs with nothing but the power cord plugged in. Also the Tap light continues to flash even when it's LED setting is set to zero in System settings.
When I flash back to OS 8.7.20 everything works perfectly. All LED lights work exactly the way they should including the controls for the Tap light.
There must be some bug in OS 9.0.5 related to the LED lamp controls.