Completion rates incorrect across devices

At first I thought this was something I’d done wrong, but the completion for these habits is different across my different devices - on my iPhone, 0/1 each, on my work Macbook, 0/12 and 0/10, and on this Mac Mini, 0/10 and 0/10.

As mentioned in some feedback, if I add a completed day before today for one of the habits, the completed target can raise from 1 to 10… which makes no sense.