Not sure what other word to use and I can't see anything with the search facility, but on a 13" TB, I'm sitting in a room with no artificial light and no bright light streaming in or anything like that. Every 10 mins or so the laptop seems to auto-dim the display to a near-unreadably dark level. It then seems to settle down and be fine for a while before occasionally turning up to 100% (draining battery). Has anyone seen this behaviour before? Is it a macOS feature/bug or maybe a faulty sensor? It doesn't happen all the time which is strange, but the lighting conditions aren't changing which makes me think its maybe a fault.