Substitute model appears in the game?

Screenshots:
http://imgur.com/h6jEcqf
http://imgur.com/IhthMwD

Attached screenshot: One of the reports in the comments.

These pictures are from the Hong Kong Pokemon Go Facebook group. One player has posted about it and asked what it is (obviously she is a newbie in Pokemon), and she said, when she tried to tap on the substitute, the game crashed. Later in the comments section, she posted a screenshot again that she saw a substitute on top of a gym again, when she tapped on this gym again, there was no substitute at all. And later, there were two players reporting that they witnessed substitute out of nowhere in the game too.

In case you don't know what a substitute is, it is literally a substitute for Pokemon to take the damage from the opponent in the main series games.

(I found one too on the gym, even though it's small, you can see it in the instinct gym behind the valor gym far behind: http://imgur.com/T6aVzvt)

So what do you guys think about it? Have you encountered it yet? Could it be an Easter egg? Or it has something to do with the future gym update?