I can’t understand why it’s hard to find an article that actually mention’s the basis for blocking things. The CNN article has it

A judge in rural southern Virginia on Wednesday ordered that the results of Tuesday’s vote not be certified on several grounds, including that state lawmakers did not follow their own rules in passing the redistricting referendum. Tazewell County Circuit Court Judge Jack Hurley also called the ballot language put to voters “flagrantly misleading.”

Sounds like this same judge already had a couple of previous attempts to stop the referendum stayed by the state supreme court.