There is a long history of PM showing parts in their promotional images and box pictures which are not actually in the box. To be fair, this may happen less in 'modern' times (in the past, for example, fixed-wrist klickies were shown on the box but free-wrist klickies were inside, but that is a long time ago!).
Nowadays, it seems that if stock of one part runs out, they may substitute a similar (but not necessarily identical) one. They obviously don't change the box picture or reprint the instruction sheets. There are many examples on PlaymoDB of set inventories containing duplicate part numbers (Heather lists the alternative part numbers and descriptions but does not give a quantity in the text set inventories), perhaps where the precise contents of a set have changed over the set's lifetime. (Have I got that right, Heather?).
It's frustrating that sets and parts vary, but no doubt Geobra think that the variations are not incompatible with the fact that these are toys, not precision surgical implants or whatever. It doesn't affect the play value, folks!