Matt spoke at length on the shadow problems earlier this month. If you wish to learn more about them I would recommend speaking to him

[That said she adds:]

I haven't experienced them quite as much as you have so far. I did see the face of one of my colleagues that disappeared shortly after I noticed him and that seems to be connected to them as well.

Matt did mention the Church in Heliopolis might have more information that could be helpful in understanding what might have led to these Shadows but would need a high-ranking Meridian to be able to access them.