No, it's not...but if it were me and I had the package in hand and I had to back out at the last minute (as in this case) I'd feel obligated to at least try to pass the partially signed package on to the next notary - don't forget, this package contains original signatures of the first signer and PII of all involved.
Who's to say the package received wasn't contaminated at the point of origin? Or the first signer/notary. It's a chance taken and just use precautions.
Lastly, to the OP, if you've not made contact with anyone yet for firm guidance, I'd at least contact your signers and let them know you are going to be a no-go for this in the morning and they'll hear from someone. Then just hang on to the package until you hear from hiring party.