My curser jumps randomly after using CTRL + Space or Enter in Eclipse for C++

When I try to use Content Assist to auto complete a keyword my cursor jumps to really weird positions f.e.:

//Cursor Position before using Content Assist
          s|
          return 0;

//Cursor Position after using Content Assist
          scalb()
          retu|rn 0;

I expect and want the cursor to move to parameter. It works fine in Eclipse for Java. Reset keybindings didnt help.