Are you using a 3rd party charger?
I have the same problem when charging at work using chargepoint.
However, when charging at home using a Tesla HPWC, the since last charge information resets normally.
I also found that while using the chargepoint charger, if I stop the charging before it reaches my charge limit, the since last charge information reset works correctly.
It's an annoying bug (though not a dealbreaker)... hopefully it gets sorted out.