“They wait until the time when an issue is likely to receive, let’s say less coverage, and that’s an old trick,” Mr. Freeman said. But of the pre-Thanksgiving release of emails, he allowed, “This time it was fairly stark.”

But the timing of the releases jars with the mayor’s repeated pledge to adhere to a policy of transparency, and it meshes with a pattern that has emerged of an embattled administration that often seems distrustful of the press.

The pre-Thanksgiving email release came after months of denying reporters’ requests for those documents and many more. City officials contended that the emails were privileged, arguing that outside advisers should be considered “agents of the city,” which would make their consultations with City Hall subject to the same disclosure restrictions as municipal employees.

The emails, which were selected by city officials and contained many redactions, provided examples of the close relationship between the mayor’s staff and his outside advisers, who include public relations consultants with clients that do business with the city. City Hall had previously released two other batches of similar emails, but there are many it continues to withhold.

The email release last week was timed to coincide with the filing of papers in a court case brought by The New York Post and NY1 seeking access to correspondence with the so-called agents of the city.

Mr. de Blasio’s press secretary, Eric F. Phillips, initially suggested in a Twitter post and conversations with reporters that the timing of the release was dictated by the court case. But while the city was required to file papers on that date, it was free to release the emails at any time before or after.

In one Twitter exchange with a reporter who criticized the city for dumping the emails on the eve of the holiday, Mr. Phillips defended the action, writing: “What qualifies as ‘dump’ timing is loose. We put out a lot of stuff. Can’t all be at 11 a.m.”