It turns out Dan has been posting updates on his own Github. This version does indeed fix all the problems and is properly dated June 26. The user @maddox discovered this earlier today, thanks!
Github: https://github.com/Dan-in-CA/opensprinkler/tree/master/OpenSprinkler%20Pi/software/demos/interval_program
Forum post: http://rayshobby.net/phpBB3/viewtopic.php?f=2&t=154&start=290#p1207