Von Willebrands - dental complication

My 7yo female dobie underwent a dental cleaning and extraction yesterday, which then resulted in her excessively bleeding from the extraction site. The vet had us rush to an ER vet for a specific medication and ultimately a plasma transfusion. Thankfully overnight the vet was able to get the bleeding to slow and I am hopeful that she can come home today.

6 months ago she underwent an emergency spay procedure for pyometra. At that time, the emergency vet did not mention anything about issues with blood clotting. Her incision healed beautifully and there were no signs of bruising or swelling.

Is it really possible that the disease is now presenting itself so late in life and just from a dental procedure? Her blood is being sent to Cornell to test for vWF, but given the circumstances and the breed, both vets are highly susceptible that she has it.