biden's team packed and shipped the boxes on their own, not on the trump team's request
the covers labeled "top secret" were placed on the files and photographed, which is not correct protocol
some of the files that had the covers applied were not top secret
the files were not logged correctly and placed in the correct boxes in the correct order
there's more that i'm forgetting
but jaco's opinion that the trial being held in FL had something to do with the indefinite hold is probably right 
When SCOTUS issues its ruling on the question of presidential immunity, which should be by June or July, this case will go from "strongest case" to "Meh."
The CinC always has final discretion over classified material. Information is not like individual rights. Rights may be endowed by the creator, but classified information and other materials require a classification authority -- i.e. it isn't classified just because it was created. Integral to that authority is an understanding that the information may one day be compromised. That's termed a "spillage" if it happens on the internet.
If a person allows unauthorized disclosure, that's one level of compromise. If the information or material is given to an unauthorized recipient, that's a bit worse -- called unauthorized dissemination. Once a compromise occurs, there's an analysis required to asses the level of damage and what mitigating options are available. communication codes may be changed, locks reprogrammed, access cards changed out, etc. I've seen where computer code needed to be rewrittem and rolled out to operational units because system capabilities and limitations were compromised.
The interesting part of all these "OMG! So-and-so had classified info at their house!" is that the actual fact that the information was possibly compromised is in and of itself classified. We don't want people to pick up the paper and find out that sensitive information is now floating around unprotected. We also don't want people to know whatever it related to might now be vulnerable. Having all these reports of classified leaks seems to contradict SOP.
Hillary outsourced her server support to a private commercial firm. They were not authorized to process or store classified, nor did anyone managing the server have an appropriate security clearance. If anyone allowed classified to be compromised, it was Hildabeast. They even found copies of all the messages from her server, including the infamous 32,000 deleted files, on Anthony Wiener's unclassified laptop.
How many other copies were there floating around?