Alright, so the way I have my setup for this issue is that I have all my progress bars at the bottom of the screen, centered of course, with one on top of the other. I usually don't have any issues with bartender and I believe this is my first. I went to my character info and then to the reputation tab. I wanted to display my Dreamweaver reputation so I knew when to stop gaining rep. Upon checking the box to show it as an experience bar, the artifact power bar below it disappeared. I thought it was maybe overlapping and causing an issue there. Nope. Maybe there is an issue with the bar being enabled or faded out? Nope. I have no idea what causes this, but apparently I can only have one or the other. Minor bug, but still irritating nonetheless. Any help is appreciated. If you'd like a picture to see my setup, I'll try to attach a screenshot.
Note: the space between my exp bar and rep bar is where the AP bar should be.