The Dragonflight Patch 10.2.7 PTR is up, and although the new Timerunning content is not yet available for testing, there's a new entry on the calendar titled Pandaria: Remix scheduled this Friday through the following Monday!
As Blizzard has not given any indication that the actual event would be so limited, it seems that this could be scheduled testing, suggesting we'll get a chance to experience the content ahead of launch.