There are a few cases when the information being provided doesn't really fit...so they try and stick it somewhere. For example, you can have planes hit by multiple bits of flak as they fly over to a target..then at the target hex, it just gives the totals in the combat report. The flak isn't all in that one hex.
Also..you can suffer operational damage from flak. The flak damages your bombers...then on the return trip home, they may crash. And show up as an operational loss, not a flak loss.
The thing to note is that a plane was lost. And the closest report it could use to tell you was that one combat report. Maybe the fighter was on Air Superiority, and was lost operationally, and failed to intercept that mission...so 0 intercepted, but 1 lost.
“My logisticians are a humorless lot … they know if my campaign fails, they are the first ones I will slay.” – Alexander the Great