PSA: People with split systems in their house/apartment, get it cleaned! I didn’t for 5 years or so and it was running badly and randomly had black dusty bits blow out. Yeah, those bits were mould! I paid a place $129 and they cleaned the whole thing out and now it’s working perfectly. This is what came out of it after a chemical spray and then a pressure water wash. That bottle is 2 foot high and they even emptied it and did another quarter of a bottle drainage:
Yep, it’s disgusting. I’m happy to pay that amount every year since my working from home desk it directly below it. Also, totally claiming it on tax as a work expense.