CE After Hearing For PTSD

A couple days after my SSDI hearing for PTSD, I received a notice to attend a CE Exam. For context, I'm a veteran already on Individual Unemployability (IU) from VA.

Hearing went okay (I thought). Judge's 3rd (and final) question did result in no jobs from the VE, but the 2 questions prior did get answers with jobs.

So, I'm just confused. Is the CE because there isn't enough in my records? I have been in consistent therapy. Or is there likely another reason?