ASM Subsystem error perl[16362] when upgrading from 11.3 to 11.6

We upgraded our F5 appliance from 11.3 to 11.6 at out DR site. No issues reported when we did so.

 

When we upgraded our F5 appliance from 11.3 to 11.6 at the Production site, the ASM module started rejecting all traffic. We rolled back to 11.3.

 

We found these errors in the logs: crit perl[16362]: 01310027:2: ASM subsystem error (asm_start,F5::SetActive::Impl::set_active): Setting policy active failed: Can't locate object method "id_field" via package "F5::ASMConfig::Entity::XmlValidationFile" (perhaps you forgot to load "F5::ASMConfig::Entity::XmlValidationFile"?) at /usr/lib/perl5/site_perl/F5/ASMConfig/Entity/Base.pm line 5483.

 

crit perl[16362]: 01310027:2: ASM subsystem error (asm_start,F5::ConfigSync::restore_active_policies): Restoring active policy - policy id 7 restoration failed

 

What are the corrective measures for these errors?