I have experimented with different errors on showcase and it looks like logging seems to be working for GraphQL errors, but not application errors, which may mean that this issue is not critical as this maybe was by design (Ali Ok can confirm)

For 100% error will not appear for validation issues in graphql and 401 and 403. Marked that as blocker but also happy to downgrade that (if issue is not easy fix, but seems that we probably missing something simple)