Question on seeing mission “!”

So when im in lets say sanctuary and go to fast travel to lets say the drought ill see a few “!” Missions available but when i travel there some “!” disappear and vice versa. Is this a bug? I wish there was a mission available log or something.

Some missions that are given by NPCs on Sanctuary will show !s in their original map location.

Why would they do that makes me think i have a mission available in that area.

It happens when the NPC moves from an area to another.
For example Claptrap will move from the Drougts to Sanctuary. When you view the Droughts map from somewhere else the “!” will show there, but when you are there the “!” will move to Sanctuary.
It’s confusing if you leave side quests for later…

So i saw indo tyrant walking around and i killed it. but i never accepted the mission on the board in sanctuary. When i killed him it reminded me to go accept the mission to complete the quest. But wen i went to the board in sanctuary the mission isnt there for me to accept it. Did i complete the mission? Its not in my completed missions log.