[not a bug]Murk Strider triggers with no crit in exile

[Aswan jaguar]

Describe the Bug:
Murk Strider etb triggers even if there is no creature in opponent's exile zone and if you select the trigger it prompts to target a creature.(it doesn't return it to hand though).

Which card did behave improperly ?
Murk Strider

Which update are you using?(date,name)Which type(Duel,Gauntlet,Sealed Deck)
Manalink 2016/01/15: Battle For Zendikar v2,duel

What exactly should be the correct behavior/interaction ?
Murk Strider

Are any other cards possibly affected by this bug ?
-

[Korath]

This is correct. The "if you do" language indicates a cost to be optionally paid during resolution of the trigger (rule 117.12); targeting is done at announcement and then validated during resolution. So it's perfectly legal for a Murk Strider to scare a Skulking Ghost into sacrificing itself even if there's no exiled card for the former to select.

(I'll grant that this is somewhat complicated by the Manalink optional trigger interface, which prevents optional triggers from even being announced, when it should just keep them from resolving.)

[Aswan jaguar]

This is correct. The "if you do" language indicates a cost to be optionally paid during resolution of the trigger (rule 117.12); targeting is done at announcement and then validated during resolution. So it's perfectly legal for a Murk Strider to scare a Skulking Ghost into sacrificing itself even if there's no exiled card for the former to select.

(I'll grant that this is somewhat complicated by the Manalink optional trigger interface, which prevents optional triggers from even being announced, when it should just keep them from resolving.)

In this case I don't know if you did any work on other cards like that not coded by you/or just using previous method but there have to be many cards working wrong (which though will be difficult for me to catch anyway) as the cards text wording alone seems rather straightforward(so I won't be intrigued to search if bugged+the Manalink optional trigger interface, which prevents optional triggers from even being announced, when it should just keep them from resolving.Most probably I will report something like this wrongly again if all cards like this are not behaving the same so to become familiar with how they are supposed to be working (baring in mind Manalink3.0 limitations)even then there is a possibility I will make it wrong. I apologise in advance for any future misreports for this,truly sorry!
...and a big thanks that you try your very best to make cards compliant with as many rules as Manalink3.0 engine limitations lets you to.

[BAgate]

And again, the rules' writers show a complete lack of understanding of the English language.

I especially love 117.6: "...Attempting to cast a spell or activate an ability that has an unpayable cost is a legal action. However, attempting to pay an unpayable cost is an illegal action."

[Korath]

My work here's actually been a net negative, in terms of rules compliance - the previous method where the engine-level trigger was always mandatory, but then it popped up a dialog asking whether to activate, is much closer to how they're supposed to work. (The interface was intolerable, though, and the difference usually doesn't matter.)