This is a Flaywind Burst (5th level Sorcerer/Wizard spell), cast through Song of Celerity with a +7 INT modifier:
As you can see, DC14 is not appropriate for this spell, which should be DC10 + 5 (spell level) + 7 (INT modifier)! When I cast the spell normally, without using Song of Celerity, this is the result:
Reserve feats, however, do not seem to be any different whether they're cast from the hotbar directly, or as a Song of Celerity on-hit effect! This is a Storm Bolt triggered by a prepared Arc Lightning spell, and cast through Song of Celerity (which is innate level 4th):
As you can see, this one has the (apparently) appropriate DC21, of 10 + 4 (innate level of triggering spell) + 7 (INT modifier). I would wonder why it's not triggering at 5th, because I am a wizard and Arc Lightning is a 5th-level spell for the Sorcerer/Wizard list, but that's a different topic for a different thread.
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