I tested it on my Amp.
When I turned on the Amp, WHA recognized the Remote after rebooting. (I have to switch the WHA screen to confirm this.)
This video begins with Amp turning on.
View attachment 14489
Then just one press of the preset button and the music plays. Thus, the Remote will automatically connect to the device even after power on/off or reboot.
If it does not work the same way, I think there is a problem somewhere.
(It is possible that the issue could be caused by radio interference, but I don't know because I have never experienced that...)