Hi!
I’ve found that the relative rotation has the axes displayed in this order : YZX (picture attached).
I’ve enabled a few different option in the editor preferences but I don’t remember all of them, so tell me if you can’t reproduce this 
Hello Sly Silversnow,
I was able to reproduce this issue on our end. I have written up a report and I have submitted it to the developers for further consideration. I have provided a link to the public tracker. Please feel free to use the link provided for future updates.
Link: Unreal Engine Issues and Bug Tracker (UE-51802)
Make it a great day