NullValue{} in generated code

[mores]

I downloaded schema.json from my service provider.
I used graphql-introspection-json-to-sdl to convert it to schema.graphql
I used graphqlcodegen-maven-plugin ( 1.61.5 ) to generate java objects.
At this point the objects will not compile - it complains about:
private Integer maximum = NullValue{};
I get this same error when using gradle:
id "com.netflix.dgs.codegen" version "6.3.0" and "7.0.3"

Is this a bug with the codegen or a lack of configuration ?
I did look over: https://netflix.github.io/dgs/generating-code-from-schema/

an example schema.graphql that creates this issue is:

input QuantityRuleInput {
increment: Int!
maximum: Int = null
minimum: Int!
variantId: ID!
}