According to Jeff, https://meta.stackexchange.com/a/38180/228134
only one display name change is allowed every 30 days
there is a 15 minute grace period after each change during which you may change your displayname at will
I recently got a mod message about my name changes and they said that I am gaming the system by using other methods.
Actually I am able to change my name on the same site as much as I want without any limit.
These are my name changes I made in Stack Overflow without getting any system warning.
So There is no rate limit preventing me from changing my name.
Is this limit lifted or is it a bug? (tested on other sites as well)