Are you guys serious?
You add Instant Games plugin to a mobile app, and it behaves odd, and then you file it as a bug!? Instant Games should only be used for instant games, which is obvious.! do not just add stuff randomly to your creations.. also instant games has it's own loader, if used properly as an instant game!...
And also note that it is not allowed to use user information that is not provided by the Instant Games SDK, along with Instant games. also you are not allowed to share app id, or use any other ad system when using their SDK.
Of course I added the Instant Games plugin. I can export to Android, iOS and Instant games from a single C3 project file. Are you seriously saying you duplicate your projects just for an Instant Games export?
And I show the different Ads based on the platform its being played on, so everything works fluidly. And obviously load different leaderboards, and disable In-App purchases for Instant Games... and a few other amendments.
C3 is more than flexible enough to handle it all