One of the common bugs states Ambrose calls you each time after you level up. Which levels does he actually mean it I'd like to know for feature references.
It happened to me a few time between levels 20 and 30, and on more than one of my characters. I found it's always best to check in with him anyway, because sometimes he does have something to say. One time he suggested that my character go to Grizzelheim, which one of my characters had not done yet. So I found it's good to check in with him anyway. If he doesn't have anything to say, no harm done. You probably already did whatever he was going to say. (I think it's a bug they need to fix. I did send a bug report. They even have it listed in the "known bugs" section.) Jasmine, and Bailey