SiriusXM app volume is too low

[utmba95]

Stock Galaxy S6 here. The latest 2 SiriusXM app updates get into situations where the volume shows max but it's really quiet. Other media streams (music players) play at normal loudness. So my media volume is maxed, but SiriusXM is varying levels of quiet. Sometimes it's normal, sometimes it's quiet, and other times it's nearly silent. When I switch to Solitaire, the SiriusXM app often reduces it's level significantly, and then it comes back up when I switch away from Solitaire. Everything I've read says that Android doesn't support individual volume per app, but that's not consistent with what I'm seeing?

Any ideas how to fix this? I use tasker to set media volume to max when I connect to my car BT, but this still doesn't increase the volume. So somehow the SiriusXM volume is set lower, independently of the media volume level.