customs and immigration – Dual Lithuanian border check by same team

Sitting on an Ecolines bus Berlin-Riga which was stopped for Lithuanian border control by a single officer, taking about 5 minutes. Then the bus drove for about 5 minutes and apparently the same officer (!) drove after us and boarded the bus again with a colleague, this time performing a second check (again roughly 5 minutes).

It would’ve been more understandable if it had been separate teams, but why would the same officer decide to drive after and stop the bus after already performing a check?