I don’t care about the template. You only need these two screenshots to understand.
Description if screenshots didn't help
Any time a blank conditional is run, your project freezes, regardless of the webplayer version. This happens because the empty ability UUID is deleted when it should have a UUID zero reference (maybe a UUID of “0” so that every blank control script leads to that).
well, now given the more info, I am not sure
The More Info
For some reason, this only occurs when the control script of an if or if/else statement is run (basically, it only happens if the true statement is left blank). Control False Script and Control Script of Repeats and Draw blocks are not affected