So I'm in a single part frame made from structural members, and I do the trims to leave a weld gap (.06 in) and for some reason about one in 5 or 10 times, certain groove welds on two parallel faces that were trimmed for the weld will only go halfway or 3/4 of the way around the groove. They are very simple groove welds, nothing complicated at all. Just 2 equal width faces parallel to each other with a thin gap between them. Anybody know what might be causing this?