Frost Bomb Not Applying Exposure Correctly

On PS5. Using supports Magnified Area 2, Over Abundance 2, Spell Echo, Potent Exposure.

Exposure is only being applied to mobs on very outer edge of Frost Bomb's AOE.

Mobs inside get small initial amount of exposure but the repeating pulses do nothing until I kite the mobs to the outer edge of the visible AOE.

Have troubleshot this as much as I can. Frost Bomb is appropriately levelled for the area Im in (skill level 14 applying exposure up to level 72 mobs in Part 3 of the Campaign's interlude. Character level 65).

Thank you.