Attack Bonus Glitching

[SharpSerpent]

I'm currently playing a low level Githzerai Monk, and I'm noticing that my attack bonus varies a lot during combat (When I use Flurry of Blows). Seeing as how I only have one attack per round (base), I doubt I'm getting confused. Attacks of opportunity and target changing seem to trigger the errant attack bonus penalties.

I.E.

I'm fighting 3 goblins and a skeleton. I have a goblin targeted and Flurry of Blows is on. The skeleton attacks with his fist and provokes an Attack of Opportunity. Either on this attack or directly after this attack (Maybe even on a cleave attempt), I will make my next attack at a random penalty ( I think it was at a -5 at level 2, but other times at a 0 at level 2 as well.). After this attack is over and if I am still on the same target (Very likely, seeing as how my normal attack bonus at that level is +6 and I just made an attack at -5), my attack bonus will revert to normal.

I don't see any changes to my character sheet during this time, nor do I have any idea why this would happen. Any ideas?


::UPDATE::
Just started a fighter (Yeah I can't stick with one character :\ ) and noticed the same thing, only it would happen when I'd occasionally get about 3 attacks in a round (Regular, AoO, and Cleave). Also, when I got Great Cleave, it was very noticable, since it broke up the great cleave almost instantly (Going from an AB of about 11 to 0 for no apparent reason). Note, still have one base attack per round, and I'm thinking that has something to do with it.