It appears in this commit 29f8337#diff-20fbfedec2cd40cb531b6e2dbd28766f5da7a02a4ee77d22519204785576c320R386 the potential for a NPE was introduced (link should hopefully point to the specific line as well).

In our case it looks like this is triggered because this library adds a _service field with a null field definition. It's not clear to me if the issue is just a simple bug that the SchemaMappingIndicator is missing a null check, or if this field that is added by the apollo library is breaking some sort of contract that requires fields have these values set. In any case, the behavior of the library is not new and this worked prior to the linked commit in spring-graphql.

Although it's far from a minimal set up 😅 , you can find a reproducer here, using the testSchemaArgumentReporter test case or just by booting the example app.