In the May 4 Rasmussen poll, Blumenthal led Simmons 55-32. In the May 18 poll the lead narrowed a bit, with Blumenthal now leading by a margin of 50-39. The TPM Poll Average of the matchup shows Blumenthal ahead by a margin of 51.4-36.9.
It's a similar story with Schiff. In the May 4 poll, Blumenthal led 54-29. The new Rasmussen numbers show that lead shrunk to 53-37. The TPM Poll Average for a Blumenthal-Schiff general election shows Blumenthal ahead by a margin of 53.1-34.7.
As was reported nearly everywhere after the Times story broke, McMahon's campaign claimed responsibility for the article, saying it was based on McMahon opposition research. That could be why the McMahon-Blumenthal numbers shifted so dramatically. In any case, Blumenthal still enjoys a slight lead in the TPM Poll Average: against McMahon, he's ahead by a margin of 49.2-42.7.