Cookie persistence showing two different bIpi cookie formats

The standard cookie_encrypt policy is applied to a VIP but dev claims we are losing persistence. They are monitoring the application session Cookie which is the same throughout the session, but at some point, the bIpi cookie (and server) changed which broke the persistence. We hopped from one server to another in the same session. 

Method: Cookie Insert

There is no timer set. 

There is no fallback persistence profile.

Cookie Encryption Use policy is "Required"

Always send cookie is UNCHECKED

Default Cookie Encrypt Pool-Name is UNCHECKED

Logs show the below:

b1pi=!uYfaiwXySoDweNP1etaP4ppV7iLnwQ/GwNsIVid6nV+Lg+rvZMTnmCumPAm/w4j5Af0Z/+b+ToK0dSk=

to

b1pi=2281642924.20480.0000

Why would I see two different cookie types? How do I decode the first cookie?

What are recommended troubleshooting steps?