This weekend some eagle-eyed Fortnite players noticed something striking: players on the Xbox One and PlayStation 4 versions of Epic's (still in development) multiplayer sandbox survival game were suddenly able to play together online.

This was kind of a big deal because to date, no major game has allowed for cross-platform PS4/XB1 multiplayer; games like Minecraft and Rocket League have allowed for just about every other cross-platform combo (PS4 and PC players, Xbox One and Nintendo Switch players, etc), but not across Sony and Microsoft's flagship consoles.

While the developers of these games and Microsoft representatives have long been politely public about their interest in seeing XB1/PS4 cross-platform play, Sony has so far shied away from the idea. 

"We have a contract with the people who go online with us, that we look after them and they are within the PlayStation curated universe," Sony exec Jim Ryan said this summer, in response to a question about why Minecraft on PS4 would not support cross-platform play with Xbox One consoles.

"Exposing what in many cases are children to external influences we have no ability to manage or look after, it's something we have to think about very carefully."

For its part, Epic appears to still be on board; a company representative told Polygon today that yes, Fortnite was in fact briefly cross-platform across PS4/XB1 due to a "configuration issue", but that the issue has since been fixed.