Something has Changed

A couple of days ago I got to level 72 of my current Salvador character on the PC. On all other visits to level 72 the XP bar stays static right at the beginning of the scale and does not move. This time the more battles I get into the more the XP level climbs up the scale. The only difference from other characters is that my current Salvador has finished the Fight for Sanctuary DLC. Has this caused the change? What happens when the XP bar is full? Does the game stop or crash?

As you own Fight for Sanctuary the level cap is now 80 so you’ll continue to level like normal until 80 where it’ll stop.