Scenario: Play All is in effect.
Someone has the Time Traveler.
They acquire a Time Portal.

From what I can tell this causes an infinite loop: they play the Portal, they rummage for what they want, play it, and the Portal returns to their hand. Since they’re in Play All, they play the Portal, they rummage for what they want, play it, and the Portal returns to their hand, and so on.

A: This doesn’t break the game because of something very important about the Time Portal: using it ends your turn instantly, so no infinite loop.