One time slot not assigning to correct service provider

I asked this previous but never really got an answer to this. I need to have the appointments+ plugin automatically booking to a certain service provider. The time slots for 7am and 9am work fine and book to "Genesis Carpet 2". But when they try and book for the 12pm slot, the service provider changes to "Our Staff". Thank you for all your help.

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OLD Thread (Started with a different question, and discovered this problem):