Esther 5:1,5:4 says that Esther made the first feast on the third day of the fast.
Earlier (4:16), Esther tells Mordechai that she will also fast for three days.
Did she eat at the feast, or was she still fasting?
Alshich (to 5:5-8) says that indeed she didn't eat at the first feast. Among many other things, this explains why the first one is just described as "the party which Esther made" (5:5), while to the second one Achashverosh and Haman came "to drink with Queen Esther" (7:1).