They could've just unplugged the server from the internet if it's vulnerable.
United States national ballot records must be kept for 22 months, and then they are likewise disposed. Florida kept (keeps?) its ballots especially long after the 2000 recount.
When a lawsuit is filed (or even when you reasonably know lawsuit will be filed), you can not legally destroy evidence related to it, even in the course of otherwise routine document destruction.
In state agencies and other large orgs, it's common to receive mass email orders from legal to preserve all documents and communications related to matter under dispute, regardless of normal retention policies, with reminders of severe legal consequences to the org and dire personal consequences if the directive is not complied with.
My claim is that this sort of action in itself is not bizzare.
That it was done with a pending lawsuit is bizzare. Whether it was due to malice or incompetance remains to be seen.
There was a special election in Georgia on June 20; the servers were wiped two and a half weeks later on July 7.