There is no such thing as an NDA for government employees. This has been discussed elsewhere. It runs afoul of Federal whitsleblower protection acts and such.
Besides if that were true then Bob Woodward a a couple of others would have been tossed in jail or taken to court for NDA violations over the books they wrote about a particular President or Presidents.
And if everything the President does were actually that classified...they wouldn't post his daily schedule on an insecure website or send it out to the media or talk about it in the daily press briefings.
@txradioguy BZZZT wrong I've signed plenty of them. I have copies of ones I've singed with OPM, DOD, TSA, DHS, DOS, FBI, NRC, IRS plus some state ones. There are a myriad of laws which prevent people from talking about what goes on in their govt workplace. Most of it is classified but nearly everything is FOUO (For Official Use Only) and ANY unauthorized release is a crime.
Anyone with a security clearance has signed them. Everyone who has access to a govt system is required to undergo the training.
So you may have discussed it but you are wrong. Whistleblower protection does not protect the willy nilly release of govt information.