Thalakos Deceiver - Incorrect resolution with copies (EndOfGame and Custom duration problem)

https://gatherer.wizards.com/ST/en-us/0/thalakos-deceiver

According to the oracle text, _Thalakos Deceiver_'s ability to steal creatures is a permanent effect. The creatures do not return to their owner after _Thalakos Deceiver_ leaves the battlefield.

Use the Gatherer oracle text linked in the issue as the expected behavior, then locate the Thalakos Deceiver card implementation and the resolution paths for copied abilities, EndOfGame, and custom durations. Verify that stolen creatures remain under the new control effect after Thalakos Deceiver leaves the battlefield and that the behavior is consistent in those cases.

Written by the indexing model from the issue text.