when I try to set a relative reminder to "0 minutes" it is set to "10 minutes" instead. I just tried with a couple of tasks and can consistently reproduce this behavior.
Thank you for your report, I will pass it to the developers and we'll look into it as soon as possible.
For now, as a workaround, you could use an absolute reminder and, for example, type <remind to at 2pm> within the task's name.
This issue has now been fixed.