Hmm, strange, not heard of this problem before.
1. It sounds like some sort of tutorial system is set up, I vaguely remember those appearing as ? bubbles way back when before I switched them off rofl. Have a look through the tutoral options and see if there is anything different between those characters that it occurs on compared to the ones that it don't.
2. What other addons do you have ? Have you tried running nUI without any addons just in case it is a minimap button for one of those addons you have installed ?
3. I've not noticed my titan bar doing that disappearing act but perhaps there is a setting you have chosen that hides it unless you mouse over it. Did you try moving your mouse over it when it disappears in case it was something like that ?
4. Finally, could you attach a screenshot of an example or two so that we can visualise better what you are describing.
See what happens when you look at these and we can see if something leaps out at us
