Another perhaps “bug” with Mist Form. I don’t know if this is the intended mechanic also, but you don’t receive specific boons while in Mist Form. For example, if I use Mist Form followed by Glyph of EH, I receive the 1 boon associated with my attunement. What I don’t receive is the 3 Might from the trait Spell Slinger (fire) when using Armor of Earth, Lightning Flash or Cleansing Flame while in Mist Form. This is also true for Soothing Disruption where it does not give me additional duration on vigor and regeneration.
Again, to clarify, with the traits
Mist Form → you receive the Might, Vigor and Regen
Using a cantrip during Mist Form, you gain the effects of the cantrip itself (IE protection, stability of Armor of Earth), but not of Soothing Disruption and Spell Slinger (Might, Vigor and Regen)