Based on Dawn Chorus's perk description ("all of your burn effects last longer") I expected solar grenades to do more damage with Dawn Chorus equipped. But I tested on Kalli and get the same exact damage value with and without Dawn Chorus. That leads me to believe that either 1. Dawn Chorus is bugged for this use case or 2. Solar grenades do not apply burns, which would seem strange. I hope this wasn't some kludgey fix for the "problem" with Necrotic Grips earlier this season, but I guess I don't know for sure whether solar grenades were applying burn back then since Dawn Chorus wasn't working at all at that time.