Hi @phemmer
As a bit more explanation from the ACME Spec:
A client responds to this challenge by constructing a key authorization from the "token" value provided in the challenge and the client's account key. The client then computes the SHA-256 digest [FIPS180-4] of the key authorization
These records are related to the Authorisations which will change when you do a renewal as they are only valid for 30 days.
Andrei