It sounds like there's an N in dzieki. Would you normally hear that when Poles talk?
It depends, in more casual conversation sometimes ę may get "shortened" and sound like 'en'.
With hyper-correct pronunciation (like in a theatre) - no. But often in everyday conversations.
I heard that saying dzieki as opposed to dziekuje can be considered rude in certain contexts... like sarcasm almost so to be careful when to use this, is this true does anyone know and how can one know?