hexed pier
When you right-click the Anahita buff icon (Also works with the Cloud Elemental, I'm not sure about the others) when you have Heart of the Elements (HotE) equipped as well it'll cause both of them to get repeatedly summoned which can also deal damage to nearby enemies if HotE isn't in a social slot.
I'm using Windows 10 and the mods I run are Calamity, Calamity Music and Magic Storage.
This happened to me on a single player world.
(I hope I didn't make any mistakes making this bug report, this is my first time doing this)
wheat slate