Collectible Card Game Headquarters

Describe the Bug:

1. You can't unmorph Kheru Spellsnatcher unless there's a counterable spell on the stack.
2. If it counters a morphed Zoetic Cavern, you're able to play it from exile as a land.

Which card behaved improperly?
Entirely Kheru Spellsnatcher's fault for A; mostly Zoetic Cavern's for B.

Which update are you using? (date, name)Which type? (duel, gauntlet, sealed deck)
Dev master head, 63a78a1.

What exactly should be the correct behavior/interaction?

1. If there's no available targets for a trigger when it's announced, it just gets taken off the stack. Absolutely nothing says you can't perform an action that would cause a triggered ability without a valid target to go onto the stack.
2. "You may cast that card without paying its mana cost for as long as it remains exiled." excludes playing a card as a land. So you'd be able to cast it as a morph, but not face-up.

Are any other cards possibly affected by this bug?
Lots and lots of related problems all over for the Zoetic Cavern-specific part. (Though some of these effects, e.g. Spelljack, say you may "play" the card, in which case you could play it unmorphed too.)

Other cards with targeted turned-face-up triggers (I haven't tested any; cards not in Manalink are struck through):
Most likely (they target a spell): Mischievous Quanar, Silumgar Spell-Eater, Stratus Dancer, Voidmage Apprentice, Willbender
Moderately likely (they target something not on the bf, or during regeneration/damage prevention): Daru Mender, Den Protector, Karona's Zealot, Monastery Loremaster
Least likely (they target a creature or player): Ainok Survivalist, Aphetto Exterminator, Atarka Efreet, Aven Liberator, Bonethorn Valesk, Chromeshell Crab, Coral Trickster, Daru Sanctifier, Dragon's Eye Savants, Echo Tracer, Efreet Weaponmaster, Guardian Shield-Bearer, Hidden Dragonslayer, Horde Ambusher, Icefeather Aven, Jeering Instigator, Kolaghan Stormsinger, Master of the Veil, Mistfire Weaver, Nantuko Vigilante, Patron of the Wild, Ruthless Ripper, Shaleskin Plower, Shaper Parasite, Silumgar Assassin, Skinthinner, Skirk Marauder, Skirk Volcanist, Temur Charger, Temur War Shaman, Weaver of Lies, Wingbeat Warrior, Woodcloaker

I confirm the 2 main bugs. I didn't test the rest so far.
Mischievous Quanar, Silumgar Spell-Eater, Stratus Dancer, Voidmage Apprentice don't have this problem can be unmorphed at all times.
Den Protector, Monastery Loremaster can be unmorphed with no target.
From the 3nd group I tested only Chromeshell Crab which works without opponent creature to target.

Fixed Kheru Spellsnatcher can't be cast with no target in commit c652f9eb.