Dragoons not allowed to use Stun? (Low level Dungeons)

[Ultimatecalibur]

Then why can I get hit with a full 20 second gravity 10 times in 30 seconds?

Nyalia is slightly off. All 8 of the common status ailments (Poison, Stone, Heavy, Silence, Stun, Slow, Sleep, Blind, Bind) have resistances and therefore diminishing returns. The "mounted" status disables the diminishing returns effect on Heavy. Other rare or enhanced status ailments (Poison#, Stone Curse, Leadened, etc.) are not effected by resistances so therefore can not be resisted.