Possible Cassiopeia Movement Bug on her E?

In any game as , I've recently seen an interesting issue pop up. Whenever I've ordered her to stop with S so she doesn't attack anything near her or move, and then E anything within cast range so she doesn't have to move to cast it, she casts E and then immediately starts trying to run into the enemy fountain. I'm not sure this is an intentional feature, as I don't think Riot supports intentionally feeding, so can someone assist me? I'm not sure how long this has been a thing or if it's been brought up before cause I've just recently started playing Cassiopeia.