Caban held a 1,090-vote lead with 99% of precincts reporting on primary night last week. Katz took the lead by a thin margin Wednesday thanks to a count of some 6,000 paper ballots. Cabán’s camp emphasized the Board of Elections had invalidated 2,329 affidavit ballots. A source with knowledge of the count said that 1,662 of those were invalidated because the voters were not enrolled as Democrats. Another 144 were not registered voters, according to the source. The remaining affidavit ballots had problems with proof of residency, among other issues, the source said.