No HRM announcement when continuing a tracklog recording

I have my Oruxmaps setup to announce my time, distance, average speed and HRM data every 5 Km. I've discovered that if I stop the track log during a ride (when we stop at a cafe for a drink for example) and then continue the tracklog once we start again that the HRM data is no longer announced but the HRM data is being logged to file as normal so it's just the announcing that doesn't work. If I stop the HRM as well as the tracking when we stop and then start the HRM and tracking when we start then the HRM data is announced as normal.

I'm using the latest version from the market, with a Galaxy S2 running stock Samsung 4.1.2 firmware. I also use an external Holux M1000 bluetooth GPS receiver when recording my tracks, and a Zephyr bluetooth HRM monitor.