Scheduled reminders set to run more than once per day will send out repeatedly

Scheduled reminders set to run more than once per day will send out repeatedly during that day.

I have a Membership Expiration reminder set to run 3w in advance of membership end date. I had my cron job set to run hourly and scheduled membership reminders (since the 4.5 -> 4.6.2 upgrade) send every time the cron job runs during the day that is defined to be 3w in advance. It does not repeat on the 'wrong' day nor is the expiration notice set to repeat. Setting the membership notices to be sent 'daily' instead of 'always' "fixes" the issue (one notice).