The wrist heart rate on my epix 2 stops measuring when connected to an indoor bike

Hey, I ran into an issue today at the gym while using an indoor bike. The bike doesn't have a heart rate sensor and can only send my cycling power and rpm data to the watch. Even though the green LEDs on my watch were on, the heart rate sensor didn't work during my workout. I've got the latest update (15.77) installed, but the problem persists. Has anyone else experienced this and found a solution?