Whenever I try to execute a function manually I get an error that the schedule is a required field (even though Now is selected). Not a huge deal, I can obviously work around it and most of my functions are executed by other mechanisms obviously, just thought I'd bring it up in case it's not been flagged.
TL;DR
Title: Immediate Function Execution Bug When Schedule Field is Empty
Developers have acknowledged the bug and a fix is expected in the next release on Monday. In the meantime, you can work around it by setting the schedule field even when performing an immediate execution.