I forgot about subtasks, they add that as well. Those are tricky though it seems because if you deleted the subtask, the arrow remains.
To be honest, I’ve never relied on that symbol. I could use it maybe when I’m working through adding a bunch of new tasks to a project when I’m planning to know which ones I’ve added stuff to I suppose, but I probably wouldn’t knowing that comments and subtasks could have removed the arrow as well.
There’s a post out in feedback for this now you can up the count on: