Confirmed Nadu not triggering when targeting Dryad Arbor with Sylvan Safekeeper, sacrificing the Dryad Arbor

[Ahayzo]

Game ID

884954836

Sylvan Safekeeper has the following ability

Sacrifice a land: Target creature you control gains shroud until end of turn.

You can target a Dryad Arbor with this ability, and then sacrifice that Dryad Arbor as the cost for the ability, because targets are chosen before costs. This is correct on MTGO. However, if Nadu is in play, Dryad Arbor also has the following ability

Whenever this creature becomes the target of a spell or ability, reveal the top card of your library. If it's a land card, put it onto the battlefield. Otherwise, put it into your hand. This ability triggers only twice each turn

Targeting and sacrificing Dryad Arbor in this way should trigger that ability, and allow it to resolve, but on MTGO it does not. Rule 602.2b says that the process for activating abilities uses rules 601.2b - 601.2i for casting spells. 601.2c states the following

If any effects say that an object or player must be chosen as a target,
the player chooses targets so that they obey the maximum possible number of such effects
without violating any rules or effects that say that an object or player can’t be chosen as a target.
The chosen objects and/or players each become a target of that spell. (Any abilities that trigger
when those objects and/or players become the target of a spell trigger at this point; they’ll wait
to be put on the stack until the spell has finished being cast.)

As the bolded part says in the comprehensive rules, as soon as you declare your target during the process of activating the ability, anything that triggers off of becoming a target triggers then, before costs are ever paid. So Dryad Arbor is still in play, still under your control, and still has Nadu's ability.

By those rules, you should be getting a card from the Nadu trigger here, but you do not on MTGO. This bug likely happens to all "becomes the target" abilities, but Nadu is the only one I have personally tested and confirmed.