Got this when I just finished a Private Team game:

Your win record for Private 4x2 team games on this board is now 1 / 1 (50.0%)

1/1 isn't 50.0%

The other stat:

Your overall win record for Private 4x2 team games is now 1 / 2 (50.0%)

Appears correct though.

The stats on my Profile appear to be correct.  Not sure if this only affects Teams and/or Private games, but will watch calculations too.

Thanks!