I have a bug with Dave, as well. Whenever I click on his portrait on the right hand side of the screen, one of the voice quotes for "Yes?" comes out as a glitchy, corrupted noise, sometimes replaced with a generic sound effect whenever I'm in battle. So far, that's the only bug I've had with him. Does anyone else have the same bug?
Keep in mind, I may have installed a version of Glam's NPC Pack via the EE Mod Setup.