make generate error: json: error calling MarshalJSON for type json.SimpleJSONValue: value is not known

I have followed the steps here to create a new provider: https://github.com/upbound/upjet/blob/main/docs/generating-a-provider.md

On step 8, when I run "make generate" I run into this error:

scraper: error: Failed to scrape Terraform provider metadata: cannot scrape Terraform registry: failed to scrape resource metadata from path: ../.work/dmacvicar/libvirt/website/docs/r/coreos_ignition.html.markdown: failed to convert example manifest to JSON: failed to format as JSON: marshal json: json: error calling MarshalJSON for type json.SimpleJSONValue: value is not known

I'm using Ubuntu 22.0 as my environment.

Follow docs/generating-a-provider.md through step 8 and run make generate in the Ubuntu environment described. Start with the Terraform metadata scraper error for ../.work/dmacvicar/libvirt/website/docs/r/coreos_ignition.html.markdown and trace the failed example-manifest JSON conversion; done means generation completes without the reported MarshalJSON error.

Written by the indexing model from the issue text.