Translation:I am almost sure that it was called that.
My scribbling..tells me that there are 3 reasons to use the imperfect in a subjunctive sentence.
Past tense in the main clause.
Conditional in the main clause.
PRESENT Tense in the main clause....with a continuous action in the dependent clause.....a past action with the typical function of an imperfect.
E.g ... Penso che Mario andasse spesso in Francia.