Ektar seems to be kind of sensitive to lighting conditions. You didn't mention the conditions under which the two rolls were shot---is there any chance that you just hit the "sweet spot" for lighting on the second roll?

The I-61 L/D is *very* well thought of, certainly. Color rendition is so subjective that it's hard to quantify, of course, and you may just like the way one lens/film combination handles color and not the other.