It seems somewhat out of character for Jenkins to get so concerned when he learns that the LITs have lost Baird in "And the City of Light", until the end of the season when you realize that she's the linchpin in his Batman Gambit against Dulaque.
Or it can show that he's beginning to care about the team.
In The Librarians S3 E06 "and the Trial of the Triangle" Flynn uses hypnosis to herd airplane passengers through the plane door into the Library without inducing panic nor the truth about magic before the plane flies into the Bermuda Triangle. Only, he ends up making them all think that they're pigs. The chances of him still getting them all out? When pigs fly...
Learning that the Guardian's primary responsibility is to keep the Librarians on the straight-and-narrow makes Nicole Noone's tenure as Edward Wilde's Guardian a complete and utter failure, in addition to the complete betrayal he pulled on her. It probably contributed to her quitting the post and leaving Flynn after the events of the first movie.
And what's worse? Edward Wilde is mentioned, specifically, though not by name.
And then Season 4 reveals that she actually didn't quit; ohno...
Thanks to the Cosmic Retcon at the end of Season 4, pretty much everything we saw in Season 4 ended up not happening. This means that Fortuna and Santa's evil brother are still out there causing chaos, people are still trapped in trees at the team-building camp, Havenport is still under the control of a fairy, etc. And did Darrington Dare die at age 40 or was he unaffected by the retcon? The silver lining is that Flynn and Eve remember everything that happened, which means they can help the other Librarians sort things out a lot faster this time.