I’ve noticed that Gypsum next to the new daily reset still has it’s old 18 hours cooldown from dropping.
as example, when you earn your emerald gypsum at 5am after the daily reset you can drop it again at 11pm after the 18 hours cooldown is over.
i’ve only seen it on emerald gypsum, for diamond gypsum it doesn’t quite work, you only drop one additional hidden stash 18 hours later.
might also work wth other gypsum, but getting groups for arena/expedition/portals is rather difficult this early in the morning.