Class Trait XP Inconsistency

I have noticed there that the time it takes to "charge" up your traits can vary significantly match to match.

I play a lot of breakthrough and the fastest I see them charge is even before we have moved past the first objective or under 2 minutes usually. Sometimes they are barely charged by the end of the map and the score I see on the scoreboard indicates I should have mine charged. Meanwhile I see enemy UAVs circling around which means others have already charged theirs and I'm at the top of the leaderboard with maybe the first 2 charged.

The only consistent thing about it is when I first start playing for the day the traits are more likely to charge within first 2 minutes of the game. Additionally I have actually seen my score go backwards. A trait is about to charge but then I die and it resets back to the bottom of the trait and when I get the final trait, I can somehow activate it again and again

Has anyone noticed this or am I missing something?