Valdez (and others) can plead ignorance when it comes to record retention, especially if the records were on their personal devices. They might get admonished (when they've already left the office so who cares) and Shannon's case ends with a lesser settlement because without the incriminating records his claims can't be completely confirmed, but there's enough possibility so neither side will risk a court battle and settle.
Look at the result of that hearing against Valdez, with the result being a public censure. With that precedent set do you think if she said she may have deleted some texts related to the case, she'd get any worse of a punishment than that?