Audit log shows lowercase username when renaming a user

Issue Summary

Check audit log after renaming a username.
If the username contains both lowercase and uppercase letters, the username before change shows lowercase username.

It should show original username with both lowercase and uppercase letters. 

Also, the username after change show both lowercase and uppercase letters.

See detail in below screenshot.

Steps to Reproduce

1. Create a user, and the username has both lowercase and uppercase letters.
2. Changed the username
3. Check Audit log for rename operation.

Expected Results

The username before change should show the original username , with both lowercase and uppercase letters.

Actual Results

The username before change shows lowercase letters.

Workaround

Currently there is no known workaround for this behavior.