Lost energy kits

[Monopolize]

So last event (Marvelous), I only crafted energy kits but did not use them because I prepared for the Goblin event. Just right now, I checked my inventory and I found out that all of my energy kits were gone. Does crafted energy kits can only be used on the event where you crafted it? and if not used on that event, it will be gone?

[im jeff]

They remove them after each event

[Monopolize]

They remove them after each event

I wasted my time 0.o. Thank you!