The heart rate from my Jabra Sport Pulse BTLE HRM is displayed on the Ghostracer app on my watch, but it is not displayed in the {shr} tag on my WatchMaker watch face. The {shr} tag always displays 0.
It doesn't work on a LG Urbane either, then again there is no documentation on it so perhaps there are restrictions (which aren't demonstrated by all the sample code I have managed to find).
I should have added that WatchMaker on watch has all required permissions enabled (which includes "sensor"). It is also able to get the heart rate from a tap action which uses Google Fit.