I’ve been having a little play with this and there does seem to be some discrepancy between times/dates input and time/dates displayed.
For a suspension of 1 day (the pre-entered default):
And for a custom suspension of 1 week:
In both cases the email was an hour off, and any suspension longer than a day rounded out the time to midnight, and also knocked a day off the date in the email version.
Edit: Making sure I got all the right screenshots along the way clouded my thinking. 
It’s because it’s knocking an hour off 00:00 which causes it to be a day early. So, it’s more about the lost hour between input and email. And @Don lost two. 