Did you run 'revalidate and save' after the upgrade? If not, can you please run it once?
You can run 'revalidate and save' that comes with Pega OOTB from "Designer Studio > System > Release > Upgrade > Validate > Revalidate and Save." you need to run it by selecting rule type and ruleset name. If you want to run 'revalidate and save' in bulk, you can use Pega7 upgrade accelerator pack (formerly ECS Upgrade Utilities), it can be downloaded from https://pdn.pega.com/exchange/components/pega-7-upgrade-accelerator-pack
Please check the guardrail score after running it and let us know.
Hi, Your application score may not be zero(it can be lower number). I couldn't recollect exact Report Name, but i would suggest you to play with complaince score report to filter the rulesets specific to your applicaiton. This will actually help you to identify which ruleset/type has problems.