My airbrush is doing weird stuff

I used this airbrush for about a year. Took it apart after every use to clean it. Re-assemble it and use it. No problems.

Yesterday the small part of the nozzle got stuck on the needle (probably pushed it too far in while i was distracted). Anyways took the whole thing apart, also trigger etc., gabe it a good clean, replaced needle and nozzle.

But now my airbrush works differently than before - when i push the trigger down, before it would just release air. Now it immediately releases air with paint. When i pull the trigger back it releases more paint.

Where did i mess up? I assembled it as i always did, spring is inside, trigger correctly put in etc. Was my airbrush working wrong before or is it wrong right now? It's the Fengda FE180K.