You're right on both instances. I could be wrong, but still trying to find the pattern so we can help make a guide!
It was just a theory, from my experience, every time I get a False on that script and I head to the dreamway, I end up with a screech instantly.
Also from my experience, every time I get a true on that script after logging in for the first time after the daily reset (without even being in the dreamway that day), I just won't see a screech that day.
I don't know why it wouldn't make sense to trigger a roll for every druid upon log-in, surely this is done with other features, maybe with garrison missions? It could be a process attached to that.
The reset is due in over 2 hours, I'll test it yet again, like I said, I noticed this weeks ago but the bug that set the other 6 scripts to false threw me off when I tried to find patterns, and the behaviour has been consistent since the fix was applied. Others can test and prove me wrong