The recently released Elder Scrolls 5: Skyrim patch 1.2 appears to have broken character resistances and made some dragons fly backwards.
Resistances protect your character and AI monsters/characters from a portion of harmful effects, be they fire, ice and lightning magic, or things like diseases and poisons.
As it stands, players take full damage, no matter what enchanted gear, race bonuses or perks they have.
The other effect, as mentioned, is that some dragons now fly backwards - evidently bored with hours of flying face first.
The patch appears to affect both PS3 and Xbox 360 versions of Skyrim.
Note that you can refuse to update Skyrim to patch version 1.2. You won't be able to play the game while online if you do, though.