This is a Paradox game - are you surprised by a paradox? To resolve the paradox, imagine that is an official state secret and the other is the one they print in the newspapers - do not ask after our uncounted dead. Very realistic explanation indeed.
Game experience has shown that losses that might be considered combat losses (such as manpower in units lost in overruns, for a hard-to-miss example) have been omitted from the war contribution screen total. Maybe the fix is in on that detail.
In any event, if both your screens state the loss from the same events, obviously it still does not work in a non-paradoxical manner and you have to use each number for what it is worth.
It is cleaner to get war contribution by strat bombing and occupation anyway.