Am having an intermittent problem. My MacBook Pro screen goes black, red battery indicator then comes on but the battery is charged to at least 50%. Soon as I plug it in, this goes off. Initially happened when I bring it out of sleep mode, but is now doing it when I boot it up. I checked battery health and it shows as good. Is this a software issue, battery or ? It started after I upgraded to Catalina. My MacBook is about 18 months old.