Name change - Adding a middle name

Hi, some time ago I wanted my middle name being added to my profile, since I am credited here in Germany with it for a decade now. Unfortunately - some time after the change  by Imdb- I learn that all my previous credits are now formatted with a (as Christian R...) at the end, which is not correct at all. Even my new credits - after the name change - say (as Christian R...) That makes a name change superfluous in my case. How can I change that back? Sorry for my english, best. C.