I'm having problems with my game where the "fortify one handed weapons" enchantment doesn't add bonus damage to daggers. The enchantment does affect other one handed weapons, such as swords, maces, etc. Being an assassin type character, this is quite annoying. I was wondering if this is intentional or a glitch in the game.

Probably a glitch, I don't think someone at Beth just decided to hose Assassin type characters.

I've noticed that its not adding the percentage of damage it should. So if for example your using a simple steel dagger the damage bonus may be so negligible that the number does not increase.

For instance my weapon damage increases more when investing a point to one handed damage, which increases it by 20%, than when I put on enchanted gauntlets that increase one handed damage by 29%... too many bugs!!!