[MrWong]

There were a couple of incidents that hinted to Zee's sexism.

The 'come on boys... Oh and you' remark.
When he let the door slam in girls face.
Completely sidelining Natalie and ignoring her request to look for potential businesses in the phone book.
Then on You're Fired he tried to blame Leah for buying the wrong robe... because she was sub team leader. -___-

However the biggest red flag regarding his sexism was bringing Leah/Nat into the boardroom instead of Neil/Kurt. Who were both responsible for task losing decisions - Flag dimensions and wrong robe.