Forerunner HR Broadcast & Varia

Up to about one or two months ago I've been using the heart rate broadcast function on my garmin forerunner 255, together with my garmin edge. I discovered by accident that I would also be notified of cars by the varia in this mode. This was great because I could turn off the alert sounds on my edge, not need a HRM monitor and my forerunner barely used any battery, since it doesn't record much.

After a week or two of using this setup this suddenly stopped working. I checked on my forerunner, but there aren't any settings related to the alerts on my forerunner like there are on the edge.

Does someone know how to fix this, because it was really a perfect setup for me.

PS: The varia alerts do work when recording an activity, but I'm specifically interested in the alerts in combination with HR broadcasting