I followed the instructions including using an incognito browser:

1) The report I created the schedule for still and his report's drop drop doesn't shows the "View all schedules" only the  "Create a schedule"
2) I created a schedule for another custom report and this report's drop drop shows the "View all schedules" menu  option with the submenu of  "schedule and send...."  when I click on that option the schedule I  created appears and I can edit it. So this works as expected.
3) I went back to the initial report, created a new schedule, returned to the custom reports page and I still don't see the  "View all schedules" just the create option.

At this point, I'll just assume this issue is a one-off and I'll move on.

Thank you for your help