perhaps I don’t find the right item or skill, but otherwise it could be a bug, so I will report it:
I used this Idol for a test, but didn’t need it enymore, so I removed it to my stash
But my Druid still casts maelstorm while standing around with no enemies or even using any skill. I don’t have any other of these idols, nor is my equipment with such effect.
If there is no other auto-cast source I missed, it seems to be a bug.
There are three things that I can find that autocast Maelstrom…
A large idol with Chance To Cast Maelstrom Every 5 Seconds
A Frostborn Seed Relic has an implicit Chance to cast Maelstrom every 5 seconds
Eye of Storms Unique Amulet…
If you are sure you are not using any of them, then I am not sure what the source could be and maybe this is a bug… Can you post a link to your build? Easiest way is to upload your build to Last Epoch Build Planner