New BIG-IP ASM v13 Outlook Web Access (OWA) 2016 Ready Template

I am using the template for v13.1. I updated the attack signatures as described in step 2, and this is the first line of the readme:

Update: v13.1.0/ASM-SignatureFile_20180925_171453:

Importing the policy (step 3) completes successfully, but gives me 64 lines of the following before the success message:

signature with id xxxxxxxxx (previously used in this security policy) does not exist on this system.

I searched for a few IDs via Security ›› Application Security : Attack Signatures and saw that none of them seem to have an entry. What effect, if any, does it have on the policy if the XML file refers to attack signatures that are not defined on the box?

And does that mean the XML file is outdated (and with it the policy) every time the signature file gets updated?