Yeah, they need to fix concentration. This is a known issue. It makes concentration-related spells not worth using. It would also be good to have access to a Feat like War Caster or whatever that one in Solasta is that lets you ignore the first 10 points of damage in regards to concentration checks. Or if they are going to be so free with the burning ground damage, set a minimum threshold on concentration check damage for everyone - ie. 5 damage or above.
It needs testing.
The following suggestion would be slightly more complex to implement, but a feat that allows you to ignore damage from all surface effects in regards to a concentration check would be more balanced imo. "Calloused Feet" or "Surface Hopscotcher" or "Coal-standing Master" or something.
Ignoring up to 5 or 10 damage from ALL sources in regards to concentration feels a bit too powerful for a single feat.
Implementing War Caster that grants you advantage on all concentration checks would also be a great solution (of course, in addition to making it so enemies had to either target you OR the ground when throwing a flask, not both).
