I want to apologize in advance if this is not the type of question for this forum. I have been searching around and unfortunately there do not seem to be any places specifically for asking questions pertaining to the inner mechanics of Aramaic.
This is from the "Genesis Apocryphon", Column 22.
Col. 22.7: והוא רדף בתרהון עד דבק לדן ואשכח אנון...
I understand there is a vav conjunctive before the word. What puzzles me is why there is an א before the word. This should indicate imperfect 1cs (plus the vav makes it preterite). However, in context, this doesn't make any sense at all. It would be the only 1cs verb used in this entire passage. Everything else in this section is in the 3rd person. Why the random 1cs switch this one time? The translation I have is from Daniel Machiela, who translates it as 3rd person "he found...". So what is it supposed to be?