When Columbo is at Colonel Braile's secret apartment, we see Mrs Padgett arrive outside. The audience quickly sees the backside of Colombo's car and then a shocking realization. His license plate has changed. It clearly reads 448-DBZ WHY???

(Wish I knew how to upload a photo of that on here; maybe someone can explain how).

Because the car used since 1988 is a different car. In new episodes there is the new car with the new license plate.

Hi.

Yes, new episodes have a different car, but fiction pretends that it's the same. Why didn't they use the same license plate?