I had this happen and it kindof inspired me. Before posting I searched the problem and found a recent but closed post regarding the use of the arrows in the default Layout scrap book looking good in Layout but showing mirrored copies in the PDF output.
Photo of Layout screen
Photo of PDF
I saw the old Post rearding this issue @trent commented that the issue went away if the viewport was set to Hybrid it went away. I tried that and it didnt go away. Also it was pointed out that it should get fixed in future updates. It hasnt but no big deal. Im really curious how those “native” arrows were created. Opening them by editing scrapbooks in layout shows me they arent native geometry. ( Says its a 2016 element) So im guessing they are an image of some type. To get my project done I created an arrow in like two minutes using arcs. the resulting scrapbook “component” actually worked pretty good. (I tried to find just that skp file but didnt sorry) the grips on the curves let me get pretty creative with this crude element. So Im challenging all you gifted people to create better arrows that might get included into the default scrapbook set. ( it might be a nice distraction from talking about bugsplats) Who’s game? My thought was to have the arrow with primary elements that have grips to manipulate the arrow. Im going to mess with this more although I haven had a need to use arrows in a long time.
This is what my crude arrow looks like. I couldnt figure out how to get just that file out of scrapbooks. But with those simple grips it can be manipulated to do many things.