Well a chemical smell in the bedroom area could be a lot of things. Is POT legal in your state? A neighbor camper perhaps? Smelling it outside as well adds another layer to the problem. Since your coach is a 2016 I assume this is the first time smelling this odiferousness (is that a word?)......after bringing the RV out of hibernation for the 2020 season. So first thought is a dead whatever that has nested somewhere in the coach and its thawing body odor could merge with your nasal passages.
The other thought is; can you determine what appliance needs to be running to generate the smell......you mention the air conditioner only? Do you still get the smell when all appliances are off (A/C, water heater, furnace). In some ACEs there are various types of hoses, ducts and wires that run down the utility side of the coach from city water port at the back to the wet bay location/appliances location. If any hose or duct or wire has sagged they might come in contact with a hot "whatever" to cause a plastic chemical smell........or as previous posters noted wiring overheating, but perhaps from touching a heating source. That assumes that if electric wiring is in an over-current state it "should"
trip a breaker or blow a fuse. Of course the Titanic was unsinkable too.