Thanks for your reply. I’ll try to answer your questions.
1) I never shut down or let my Mac do a full sleep. My Mac is always running.
2) I’ve encountered the problem when no audio was playing. So, after waking up my Mac with no audio playing, I’ve noticed that the icon in the menu bar was black and I had to turn it on. It doesn’t always happen, this behavior started recently. Version 1.0.4 worked fine for months.
3) I use my iMac’s build-in speakers.