Because of an issue with the raiding system being turned off for most of the Guild Wars 2: Heart of Thorns beta weekend, the event has been extended until 12:00 pm Pacific / 3:00 pm Eastern today. Players will be able to check out the new raid system along with the squad UI up until the event ends later today.
We are going to extend the beta until Noon PST on Monday - Raiding will be available the entire time (pending non disasters)! GOGO!
— Shazbawt (@Shazbawt) October 5, 2015
Source: Dulfy.net