Well, 900 of the votes were definitely fraudulent.
The votes that you are referring to were eliminated due to
illegal collection of the ballots in excess of the number permitted to be collected by a single individual
NOT because the ballots themselves were fraudulent.
It's similar to the case in North Carolina where a Republican congressional candidate hired a ballot harvesting operative that
collected ballots
illegally. They too were caught because the system to prevent that type of illegal conduct in an election worked.
In both cases it was the
voters that were defrauded who didn't realize that there ballots were being illegally collected.
Fraud inflicted upon the voters, not fraudulent ballots by illegal voters.