-health regen NOT vampiric...rare?

I recently found purple 6-9 scimitar (no req) with +10% damage always with a -1 health regen as the condition, rather than the -5 energy or -10 armor (while attacking) that I've seen more often. It is NOT a Vampiric weapon (has no prefix or suffix, just "Scimitar"). Out of curiosity, is this version of the mod rare?

yea, its just a negative to damage all the time...

No. There are four possible mods to a "permanent damage always" weapon:

-5 energy
-10 armor
-1 health degeneration
-1 energy regeneration

And their desireability are those, in order.