I do not have imwheel installed and still have this issue.
Also, upon restarting today, the issue has gone back to affecting all ten keys. Page_up is mapped to / (as well as the / key itself), and page_down is mapped to something that brings up a context menu in the focussed window. As well as up_arrow being print_screen, these are the only three of the ten that seem to be mapped to something.
I do not have imwheel installed and still have this issue.
Also, upon restarting today, the issue has gone back to affecting all ten keys. Page_up is mapped to / (as well as the / key itself), and page_down is mapped to something that brings up a context menu in the focussed window. As well as up_arrow being print_screen, these are the only three of the ten that seem to be mapped to something.