Setting constant effect cast style doesn't correct effects view
Adding spell effects incompatible with constant effect enchantments before switching to constant effect does not remove the incompatible spell effect. I've attached images where i tried enchanting an amulet with constant effect calm humanoid 1pt on target.
While enchanting an amulet with constant effect fire damage on target the edit spell effect part of the enchanting UI shows the enchantment range as "Target" however the result is an amulet that damages the player.
When switching to constant effect the incompatible spell effects should be removed (such as Calm Humanoid/creature, Soultrap, demoralize etc). And all effects should have their range changed to "Self".
OpenMW version: nightly 2020-08-08 OpenMW-f73aa9f2-win64 (Latest nightly available to download)