API cache not getting invalidated when using /reassign in merge request

Summary

After making a merge request they use the API to check if a bot is assigned to the MR. They do this through api/v4/projects/2/merge_requests?state=opened.

At first, it returns "assignees": [],

They then use /reassign <bot> to assign the bot to it.

They check the API again and it still returns "assignees": [],, after midnight the cache gets invalidated and the API returns "assignees": ["bot"],.

Steps to reproduce

Create a merge request
Check through the API
use /reassign to assign someone
Check through the API again.

What is the current bug behavior?

The cache is not invalidated and still returns old data.

What is the expected correct behavior?

The cache should be invalidated and the API should return the new data.