Question to officers - Department working under expired CBA

I have worked for the same department for the past 16 years. Every time our Collective Bargaining Agreement expires, it takes multiple years for a new one to be settled. Only once have we received back pay for the years spent working without a contract.

My question to the other agencies : Is it normal for your department to have their contract lapse each time it expires and work without a contract for a long period of time?