Ionela spawns exactly at 1640, 60, 63
To make her pop you will need to kill the other Potamide's in the area. You don't need to kill the Queen. Just stay between the river and the pond (near the waterfall). Stay on the NORTH - WEST side of the small pond. It might take a couple hours, but Ionela will spawn eventually.
Killing her is nothing special. She is level 57 and has no adds. Just a normal fight. I fought her today - May 2023
Edited, May 15th 2023 6:43pm by SweetyD