I have a scheduled email report on R Studio Connect, and I set it to run at 7AM US/Eastern time. When I first set it, after inputting the time (using my system time in the "Start Date and Time"), it read: Tue Mar 13 2018 07:00:00 GMT-0500. This was correct prior to daylight savings time.
When I go back into the options and re-set the time to 7AM, it correctly adjusts to Tue Mar 13 2018 07:00:00 GMT-0500 (image below).
Unfortunately, this is an open bug for us and the only known workaround is the manual massaging that you mentioned. We have this on our backlog and hope to spend some time on it this year to get things to behave in a more expected way.
Just to give more transparency about what's happening under the hood, the time that you put in is getting cast to UTC when it's saved in the server. The server then invokes the document based on the input time UTC, which is agnostic to any region's daylight saving time rules. When you go to look at the document in the UI later, it converts the entered UTC time into your local timezone, which is why you see the discrepancy.
Unfortunately, it's always tricky to get timezones to behave sanely for all regions, so it's taken us a while to carve out the time to properly get things one stable.
