The behavior is still erratic and not working as it should.. However, the slider, when I use that exclusively, longer jumps around. However, I cannot use both the slider or the up/down buttons. I can only use one or the other.
Some times the up/down buttons work adjusting the volume. Some times it doesn't.
The slider always works.
However, if I attenuate the the volume with the slider, then if I adjust it with the up/down buttons by say 4-5 steps, the adjustment is made on the receiver but the slider number value on the app does not change. Then, if i move the slider just one step in either direction the reciver will spring back several steps to whatever the slider was. EXAMPLE: If I set the slider to 50. Then using the up/down buttons lower it to 45, then move the slider down just one step the receiver will jump up to 49.
I'm using the most recent app version on my ios 12 Pro.