That was my immediate thought as well - CQRS doesn't fit well with the "everything should be deterministic" principle, unless they have a very different definition of CQRS than what is in common use.

In theory, it is possible to do "synchronous CQRS", where the update to your write-side is done in a single transaction with the update to the read-side, but that's not how I've ever done it in my (Scala/Postgres based) CQRS app experience.