We are using 96.5/3.5 tin/silver solder paste on our top side and I have been noticing that on some QFPs the paste forms a heel fillet, a negligible toe fillet, and does not wick over the top of the lead "foot". I am checking to see of the components have a palladium finish (I am pretty sure they do). If it turns out they do, is there an issue with tin/silver paste and palladium coated leads? We are peaking at 230-235 C (ten zone convection Conceptronics) so the boards are getting plenty hot. Why does the paste seem to bulge up at the toe fillet, but not wick onto the lead surface?