I have the same issue with upgrading from 9.1.3112 to both 9.1.3129 & 9.1.4234. I also have this issue when upgrading from WVD 1.2.x to 1.3.x. Seems to be a package error or something?
With 8.6 we already made an exclusion option in the DHCP with DHCP option 167, CA Validation; FALSE.
Perhaps this is something like that? Anyhow, friday I have a Teams meeting with a Dell engineer, to see if we can find something about this issue.