Loadfactor drops to 0%

[Spotter2004]

As the title suggests, sometimes I have a day when the load factor—for both passengers and cargo—drops to 0%

And I've noticed this happens with multiple aircraft

It doesn't happen every week; demand at the airports in question is the same as the rest of the week

Is this a glitch, or is there another cause?

Thx

[Sami]

Some major world event?

Or all of your planes in maintenance at the same time?