I believe this works on only Trinity Core servers (Abyssal WoW for sure). I am also not sure if this bug has been posted in the past, if so forgive me.
This bug only works with classes the use spell damage as their damage (shammys, mages, pallis, warlocks etc.). BUT, you can't use any more SP gear (like if you do it with a palli, you must wear ret gear.)
Steps:
1) Learn leatherworking all the way to 450
2) Take everything off except bracers
3) Enchant the bracers with the spell power enchant
4) Unlearn leatherworking with the bracers on.
5) Take the bracers off
If you take everything off (even without re learning leatherworking) and put on the bracers and take the off, your SP will still bug.
Have fun