Have you opened a case with support yet? I would definitely reach out to them, they are actively troubleshooting this issue still as I am still in contact with support and any data points they can get will assist them in narrowing down what changed.
The iPads you are working on are similar to mine, I am using 6th and 7th gen running anywhere from 12.4.1 to 13.5.1 and seeing this issue. I cannot find any true fix on my end, it's like the command to delete the profiles from the previous network was removed as part of the process when moving iPads between networks.
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