Yes, the first time a bank statement file is imported into Xero, Xero needs to learn how to use such file. It needs to “map” the different fields to Xero.

That will only happen on the first import. Should it happen on a following import (for the same bank account in Xero), it means something changed. Usually that’s due to change in computer settings:

Try to do as you used to do. If you can not, create the mapping again and it will be fine going forward.