I would think there is a plausible explanation to this. I really doubt they've been cut off by someone
It might be that she shed those Whiskas and they are regrowing. They would be much more visable than a couple of missing ones as they are so short so stand out.
She could have had an itch or something and rubbed her face quite vigorously on the corner of something rough, which could have cut them. Although, I would think the front would be cut first in that case. But you never now.
Try not to worry yourself thinking something bad happened to her