The bike in question appears to use non-Blackbox Rockshox Flight Attendant suspension, which could mean the SID Flight Attendant is in production.
The Instagram post also shows Sina's teammate Victor Koretzky using the current Epic World Cup, which does not feature the Flight Attendant SID suspension. Given the size of the SID Flight Attendant shock, a new frame design may have been necessary for XC racing scenarios.
The current Epic Evo uses a flexible stay with a linkage-actuated shock, while the Epic World Cup frame has a single-pivot suspension design with an inline shock.
The most noticeable change is the larger headtube/downtube junction and downtube cross-section, which will likely create space for SWAT storage. There's also a very low stack height and a recessed top cap in the top tube, which could allow for internal routing of the headset.
