Bug displaying free slots with multiple providers?

I have two service providers on my Appointments+ setup and the other day I noticed a bug.

Provider 1 was busy all day apart from a 1 hour slot between 1200-1300. Provider 2 was busy all day apart from a two hour slot between 1300-1500.

On my website you cannot pick your provider, the appointments plugin just displays the available slots combined for both providers and jobs are assigned manually as they come in. However for the example above if I attempted to book a 3 hour slot it would show 1200-1500 on the day in question as being free and available to book even though I did not have one provider who was free for the whole time slot.

The appointments are for my providers to go out to customers at their location so I cannot assign the first hour to provider 1 and then have provider 2 take over for the last two hours, but this is what the plugin was doing. Is there something I can configure to fix this?