ya, although it's not a bug, i think the wording of the shields are misleading
it said "spells are reflected against your opponent"
it didn't mentioned any "damage reflected"
most people will understand as "reflect all spell that target you"
so the spell poison should be reflected, but not the poison from puffer fishes as it is ability
also unstable gas should not be reflected than, as it is not a spell, but an activate ability
however, the shields don't work as what it said
so i think either the wordings or the effects should be changed