Do you have any proof that Global Game Show: Out of This World was originally released as a special?

Yes....

https://www.discoveryuk.com/series/expedition-unknown/?ss=4#episodes

It is not listed in the Discovery list of Season 4 episodes and if you watch the show he regularly does "Game show specials" as he calls them that do not follow the official release times of the main series.

Sorry, I meant: Do you have proof that the US channel aired it as a special in early 2018?. We have to follow the original airing order.

The official airing channel in the US of Expedition Unknown is Travel Channel.

Here is Travel Channels link to the episode in question:

https://www.travelchannel.com/shows/expedition-unknown/episodes/global-game-show-out-of-this-world

The official broadcasters of the show class the episode in question as Season 0, Episode 34

Here is the official list of Season 4 episodes: https://www.travelchannel.com/shows/expedition-unknown/episodes/

And as you can see this special episode is not listed.

Here is the list of specials where you can see numerous Global Game Show specials were aired (not part of official seasons)

https://www.travelchannel.com/shows/expedition-unknown/episodes/

The date and time of the airing of said episode is not relevant to its placing in a season, many many shows air specials mid season, this does not make the episode part of the season, it makes it a special.

@lorkadiscovery said:

The official airing channel in the US of Expedition Unknown is Travel Channel.

Here is Travel Channels link to the episode in question:

https://www.travelchannel.com/shows/expedition-unknown/episodes/global-game-show-out-of-this-world

The official broadcasters of the show class the episode in question as Season 0, Episode 34

Here is the official list of Season 4 episodes: https://www.travelchannel.com/shows/expedition-unknown/episodes/

And as you can see this special episode is not listed.

Here is the list of specials where you can see numerous Global Game Show specials were aired (not part of official seasons)

https://www.travelchannel.com/shows/expedition-unknown/episodes/

The date and time of the airing of said episode is not relevant to its placing in a season, many many shows air specials mid season, this does not make the episode part of the season, it makes it a special.

This doesn't answer @banana_girl question. The question is "how was this episode listed in 2018 ?" not "how is this episode listed now ?"