Hey all,

I'm in the proces of upgrading to GQL v7 and I need a little bit of help.
We have a fairly big schema and it also contains some unions. So I was waiting for the issue described in #234 to be fixed. After upgrading to v7.2 our tests are failing and I'm getting other issues now.

So, after trying to fix this for an hour, I decided to build the SimpleWebApp from the samples.
When using GraphQL.NET 7.1.1 or later I'm getting this on the first execution:

"message": "Error executing document. A different instance of the GraphType 'OutputObjectGraphType<Author>' with the name 'Author' has already been registered within the schema. Please use the same instance for all references within the schema, or use GraphQLTypeReference to reference a type instantiated elsewhere.",

And this when I execute my query another time:

"message": "Error executing document. This graph type 'OutputObjectGraphType<Book>' with name 'Book' has already been initialized. Make sure that you do not use the same instance of a graph type in multiple schemas. It may be so if you registered this graph type as singleton; see https://graphql-dotnet.github.io/docs/getting-started/dependency-injection/ for more info.",

The change log for GraphQL.NET 7.1.1 is showing me this issue I'm experiencing: graphql-dotnet/graphql-dotnet@7.1.0...7.1.1
Might this be another issue in the GraphQL.NET project or am I just totally missing something in the migration documentation?