In MagicDraw/Cameo the name of a Derived Property is parsed and sometimes displayed quite differently in column names.
For example, using the following shorthand for a derived property for "port of port" DP PoP becomes DP Po P (note the extra space), it is treating the lower case 'o' specially. If you then rename it to DP POP (note ALL CAPS) it still sees it as the same name and will still display as DP Po P (still with the extra space).
Be careful when mixing lower case and upper cases in derived property names!
If you start with DP POP it will display it as expected DP POP.