I know it's possible with TWRP, at least on the G3, to back up efs when making a nandroid and some of the earlier versions had it selected by default. If was left selected in the restore menu, then it would overwrite the existing partition. Happened to a few on the G2. But anyway, I hope you're right and it's just a rom issue.
To the OP, you know you can just restore the data partition from a nandroid, without having to go all in, right?
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