There's only one suggestion: ban placing the Grail in the Conflux. :D
Even the shifted guards and buggy passages have been fixed, and the free collection of resources using a Demon/Flyer has also been addressed. For now, these rules remain in place, just in case the fix turns out to be ineffective, but in the future, they will also be removed.
Specifically, placing the Grail in the Conflux is a backup way to gain control in the late game if it wasn't possible to obtain it through standard methods. Recently, Tvarina found himself in just such a situation during a stream. He didn't pay attention, though, so it's unclear how it ended.