The version of Scrivener in use was v3.1.3 (11945) for the Mac.
The formatting of the document was set to start new sections on “recto” pages. <$p> of <$pagecount> was included in the header definition for all pages.
Pages containing user text printed correctly, but the pages that were automatically inserted to begin a section on a “recto” page contained something like the following: 2 of 9223372036854775814
Note: I need to include the page number and count on every page, in order to ensure all pages are present in the printed document. I could suppress headers on auto-inserted blank pages, if such pages could have an optional message. In technical works, this message often reads “This page intentionlly left blank.” This might be a feature to consider, whether or not the reported issue is fixed.