So now the "un" is optional? Arrgghhh
When you talk about someone's profession, you usually omit the "un" article. For example: "I'm a doctor" would become "Eu sunt doctor" in Romanian.
Shouldn't the "Tu e fizician" be accepted here?
Nope, but "Tu ești fizician." should.
e is short for este not esti (apologies for lack of accents).