I'll test it on my Win10.
Must be the iPad, but strangely the there are no data drops from the HRM at all.
Not really needed as I never 'train' to HR anyway and I really cant be bothered to factory reset the iPad.
Just a weird Ipad app thing.
I can just open Sufferfest app and explore the workouts... open one up of the many to choose fromand not even bother to pair devices... the target scales/profiles at the bottom of the screen are there for power and cadence but HR is just blank.