Its made even worse, that in XDG_DATA_DIRS and other path environment variables have the same folder duplicated. In fact, it grows every time one opens a shell (being duplicated first, open bash they become triplicated, etc).
Tested by watch env | wc -l grow.
Here is a topic about it and a possible workaround, but I don’t know how to make the “kde launcher” clean the duplicated variables automatically.