1800 miles -- Did you oil the chain when you got the bike (zero miles ) and did you clean and oil it every 300 to 400 miles afterwards? Say 5 to 6 times? No one does on the new OEM chain and then everybody complains how crappy it is.
Reddish brown sounds like rust. Sounds like new chain time. Maybe new sprockets too. Get an o-ring chain. They are low maintenance. NOT no maintenance, but low maintenance.