Gatsby-source-plugin threw an error while running the createSchemaCustomization lifecycle

Hi. @andyrockport8 I think this is a problem with the V5 plugin. For some of my repos it works perfectly, for other repos (generally older repos) I keep getting this error.

What works for me at the moment is upgrading all Gatsby plugins to Gatsby V4 but keep the Prismic plugin on 4 rather than upgrading to 5.

Everything will then work properly.