Route L/F history

[clchat]

Just found a strange display for some of my routes. I am running a route with 2 classes (Y and C) but for some days, it shows 0% for F class in the route history like below:

Route                 Date                 Load factor
VHHK - RJAA    Thu, 22-Jul-93    Y: 95.1% C: 90%
VHHK - RJAA    Wed, 21-Jul-93    Y: 94.1% C: 100%
VHHK - RJAA    Tue, 20-Jul-93    Y: 91.2% C: 100%
VHHK - RJAA    Mon, 19-Jul-93    Y: 99% C: 100%
VHHK - RJAA    Sun, 18-Jul-93    Y: 97.1% C: 90% F: 0%
VHHK - RJAA    Sat, 17-Jul-93    Y: 93.1% C: 100%
VHHK - RJAA    Fri, 16-Jul-93    Y: 94.1% C: 100% F: 0%
VHHK - RJAA    Thu, 15-Jul-93    Y: 91.2% C: 100%

Not sure if it was asked before.