Issues upgrading to Percy Storybook v4

[jeffchew]

The problem

We have been having issues upgrading @percy/storybook from v3 to v4. We have made the suggestion of removing any ad service calls (by removing them entirely) but still seems to be an issue. The end result is that most snapshots go missing. This is observed in both our React components and Web Components versions of Storybook:

PR opened:
carbon-design-system/carbon-for-ibm-dotcom#8128

React Percy latest result:
https://percy.io/538fc19a/Carbon-for-IBM.com-React/builds/18147514?utm_campaign=538fc19a&utm_content=Carbon-for-IBM.com-React&utm_source=github_status_public

Web Components Percy latest result:
https://percy.io/538fc19a/Carbon-for-IBM.com-Web-Components/builds/18148038?utm_campaign=538fc19a&utm_content=Carbon-for-IBM.com-Web-Components&utm_source=github_status_public

Environment

• Node version: 14
• @percy/cli version: 1.2.0
• Version of Percy SDK you’re using: 4.2.0
• If needed, a build or snapshot ID: see above
• OS version: Ubuntu 20
• Type of shell command-line [interface]: Linux (Jenkins on Kubernetes)
• Storybook v5 (we are in the process of migrating to v6)

Details

When digging into the logs, it appears that JS artifacts themselves (produced by Storybook) are getting blocked, an example of what we're seeing:

Debug logs

Attached:
Deploy Preview build log 20220517.txt

Code to reproduce issue

You can probably best see using the fork:
carbon-design-system/carbon-for-ibm-dotcom#8128

Steps to build:

1. yarn install
2. yarn build
3. cd packages/react
4. yarn build-storybook
5. yarn visual-snapshot