The people who run elections know that court orders can be reversed. It is not difficult to mark who the last person in line at 7 was and then note what time that voter voted. The machines -- at least the ones in NJ -- do record time.
I would be very surprised if that wasn't a standard part of procedures.
That said, I don't see how they can disallow those votes, particularly given the fact that the Dallas County web site provides the WRONG information:
The site explicitly states that people can vote at country voting centers.
https://www.dallascountyvotes.org/in-person/
For the March 3, 2026 Primary Election Early Voting period, voters may vote at any countywide Vote Center. On Election Day, voting will be precinct-based, requiring voters to vote at their assigned party�s polling place.
When Voting in Person whether at an Early Voting Vote Center or your assigned Party�s Polling Place, voters must be mindful of the provisions established by the Texas Election Code, ensuring a smooth and fair voting experience for all.