Puppy is sick before collection

My partner and I were due to pick up our puppy tonight (deposit put down several weeks ago) , but have been informed by the breeder that she is spotting blood from her vagina today despite a clean bill of health at the vets on friday. She has been taken to the vets and has been given a possible cystitis or vaginitis diagnosis but they want to see how it progresses.
(Spotting blood is the only symptom, no issues with going to the toilet and behaviour is normal)

We are obviously completely unsure of what to do, we may have to wait for x weeks whilst the vet monitors, and miss out on so much of her early development. Or if a diagnosis is made where does this leave us? Presumably that voids any insurance as it's a pre existing condition...

Any advice would be most welcome, feeling pretty down right now