Merge request UI showing "Something went wrong. Please try again."

Summary

After creating an MR, clicking on Merge request button, will result to showing a red message showing:

Something went wrong. Please try again.

Please see attached screenshot below.

Tested on both v9.4.1 and v9.4.2

Steps to reproduce

Create an MR (at any repo and branch), then click on Merge button. It will show Something went wrong. Please try again.

What is the current bug behavior?

MR is/was actually merged despite the UI showing incorrect message.

What is the expected correct behavior?

Merge request successful