fuel filter clogging.
Snags like this are either go or no go according to the MEL( what a piee of workmanship!) However given the state of fuel at "foreign" bases as I have experienced,it is either a clogged filter
1. Visabley-fungal or other debris. but the other engine by the sounds of it is behaving ok,then it is
2 .
an indication prob as Blacksheep sugessts. At the end of the day you know where the ship has been,but if it was bad fuel the other one should have been giving hassels too,knock on wood. Are all other systems working correctly,ie jet pumps etc?
Good luck!