I think the secret is quite easy to figure out - The Red Guard are the ones causing the spike in Aberrant appearances. Whether it’s because of their use as spell components, or (as I suspect) because they have been looking for a way to transfer their minds in and take control of them. But Thaddeus attacked her because she said she had put together the data.
Imagine what kind of power they would have if someone like Goldfisch or Aisling now had full control over the Red Sage, or the Dawn Troupe.
I also wonder if the Red Guard is actually older than they claim to be - older than Myrddin - and in fact acted to try and force Myrddin to disappear when he noticed something about Aberrant breaks.
All of this is just speculation from me today, and I doubt we’ll find out until book six.