Good day,
I've set my boss up with a subscription to a dashboard that gives the current fiscal year sales. Her subscription is set to send the email at 8 AM. So far, so good, she's been getting the emails just fine, so I know that part is working okay. 
But in part of the email, she's seeing a time of 4AM, and at least some of the time her emailed result returns the value of the prior day, because, guess what, the nightly update of the underlying MySQL database also starts at 4AM. Small detail there...
So, my question is this: when a dashboard subscription hits the time to send the email (or slack update), does it refresh the dashboard at that time, then construct the distribution; or is Metabase set somewhere to automatically take a snapshot at 4AM and send that, whenever the subscription time is reached?
For now I've moved her time to get the email from 8 AM to 11 AM, we'll see if that makes any difference. Any thoughts appreciated.
*** Update: After moving the dashboard subscription time up by three hours from 8 to 11 AM, I note that the start time on the email has also been moved from 4 to 7AM. This is well past the update time of the MySQL database, so my boss reported the data returned today is good. So whilst it may not be a hard-coding of 4 AM, there is apparently a four hour gap between the origin time of the dashboard creation and the delivery. So the workaround works.