GMS 2.3+ Region Start/End markers in Sequence not working in room


I've been working on making a seamless looping animation with sequences and got pretty excited when I saw this in the manual:
(these are the pink markers at the top of the dope sheet)

For the animation i'm creating the Region Start is on frame 10 and the Region End is on frame 80, but when I play the animation in the room (it's just on an asset layer) it starts on frame 0 and restarts on frame 0 after looping. Double-clicking on the sequence in the room gives the option to change the "head" which means the animation now starts on frame 10 (when the room loads), but once it loops it goes back to starting from frame 0. Is there a way to make a sequence start at a certain frame when looping instead of starting at 0? If so it could be useful for animations with a buildup or intro