Capturing Erebix, Light's Bane

When I completed killing the boss and giving the Captured Boss Soul to Sin in Oriath, I noticed that upon immediately checking my atlas in town, it didn't show that I captured Erebix. It was only when I left the area (back to my hideout) that the little symbol on the atlas above the map disappeared.

This happened to me with Erebix. I've only noticed now. It may happen to all other boss souls when you hand them in too. I do not know as of yet.

This isn't such a big problem as I still got the bonus, it's just a 'quality of life' issue really. Still, I thought I'd let you guys know.