Looks to be a quirk in parts editor. It does that sometimes (skips pins) for reasons unknown (I have seen it before in parts made by parts editor.) I have tools to renumber svgs and fzp files so if you upload the part as a .fzpz file (upload is 7th icon from the left in the reply menu) I can fix the numbering for you and you can see what parts editor does with it (I normally edit the files directly and don’t use parts editor.) My normal work flow is described in this tutorial, and thus may help you if you want to go directly for the files as well.
Peter