I just got and EOB for an ER visit from 4 years ago. Should I be expecting a bill?

I’m in Texas and we haven’t had this insurance for two years but was covered by them at the time of the visit.

We never received a bill from this clinic. I keep every medical bill we receive and I pay every bill as soon as I receive it.

Why am I receiving an EOB 3years later that even says the claim was only processed 5 days ago? Do I have to pay this bill if I receive one?

Edit; 3 years ago, not four.