Response code 500 returned for Rate limit error instead of 429

I notice that GitLab server throws response error code 500 (Internal server error) instead of Response code 429 when rate limit is hit while creating issues using Graphql. This is observed on both on premise server (15.6)

I observed that that while creating notes exceeding the allowed rate limit server throws Response code 429 as expected.

(a) configure rate limit for Issue creation on On premise server to 5 per minute.
(b) using postman execute graphql apis to create issues, create 6 issues with a minute.
(c) Internal server error (code 500) is thrown instead of 429 (too many requests)