Brett Tolman, former US Attorney thinks he has the answer:
"Further, it is in this meeting that it is decided that the Obama Admin is not going to fully brief Flynn and hence the Trump administration on the status or progress of the Russia investigation. But what screams out is why they didn’t want to brief them—not because they were aware of any wrongdoing by
@realDonaldTrump
or
@GenFlynn
or anyone else. The real reason is because they did not want to reveal the merit less spying, unmasking and leaking against the incoming administration. Let that soak in … They didn’t want to get caught. The ones trying to catch someone in the Trump administration didn’t want to get caught illegally spying and investigating. This is why Rice’s “Top Secret” email is so important."
"This is not just a CYA but a CEA “cover everyone’s a**” attempt. This shows Obama and Biden were calling shots against Flynn and Comey was providing the ammunition.
https://twitter.com/tolmanbrett/status/1262862711039250432