"Object.getClass()" because "source" is null weblfux graphql

I am trying to return entity from mongo. Saving works as expected, but get request doesn't work.

I get error: Cannot invoke "Object.getClass()" because "source" is null at org.springframework.graphql.data.method.annotation.support.SourceMethodArgumentResolver.resolveArgument(SourceMethodArgumentResolver.java:71) ~[spring-graphql-1.0.0.jar:1.0.0]

gradle versions:

id("org.springframework.boot") version "2.7.0-SNAPSHOT"

I found out similar problem in spring that was fixed in Spring 5.3.12. But the last supported version of webflux is springboot 2.7.0.

Any ideas?