Curse + Spell cascade bug on a narrow passage

If you cast any curse with spell cascade when you're in a narrow passage, main curse cannot be casted on mouse cursor. This makes players very vulnable in such maps.
But if you try same thing without spell cascade, curse spell will be properly casted wherever you're standing.

This can be seem to be a simple bug, but it's very critical for CoC build using Doedre's undoing.