Cast When Stunned not working with some Spells

Cast When Stunned should link with any skill gem which has the keyword "Spell".

Bug: Cast When Stunned does not work with Smoke Mine, even though Smoke Mine is tagged as a "Spell"; there is no letter and you can still cast the Smoke Mine normally even though it is linked with Cast When Stunned.

Expected behaviour: When Smoke Mine is linked with Cast When Stunned you should not be able to cast the Smoke Mine normally and it should get a letter indicating the link and there should be a chance of laying the Smoke Mine when stunned.

If Working as Intended then the description for Cast When Stunned should state which Spells it does not work with.

Note that it is a general issue with many "Cast on..." support gems that they do not work as the words indicate they should. For example Cast on Melee Kill works with Detonate Dead even though Detonate Dead does not have the "Spell" keyword. I know the "Cast" keyword is counted as a Spell in this case but that fact is not well documented to say the least; the support gems need to be more clear which skills they do and do not work with.