"Kullar says that while masking is mandate and typically enforced by flight attendants while aboard the plane, you should also be careful while at the airport, where it’s more crowded and mask-wearing may not be closely monitored by staff. " [from CNBC]
“while” is a conjunction that connect two sentences.
The first "while" acting as a conjunction means "although" and it is followed by a complete sentence, right?
I think that the second and third "while" also acts as a conjuntion and means "when". But why aren't they followed by a complete sentence？