The new update still shows unavailable slots as "busy" if there's just 1 service provider.
In the settings there are "no specific provider" and providers. When you enter the initial schedule page, even if the single provider is automatically chosen, it doesn't properly allocate the unavailable slots, but still show "busy".
However if I press "show availability", (again, even if it's just ONE provider, and even when that one provider is automatically chosen and displaying), it'll now properly show the unavailable slot as unavailable.
A little difficult to explain as the bug is a little complex. Hope this makes sense.