i've had this battery a few months now and even after the update last week I have not seen this error. worth a heads up to those who have this battery installed.
On August 1st we started seeing Tesla roll-out the latest software update to our vehicles, 2020.28.6, and in this update process it appears likely that you may receive an erroneous 12V battery alert on your Model 3 vehicle.
At this time we have only identified this issue in Model 3: none of our Model X, S or even Y clients have experienced it. If you have a Model 3 and just updated or are about to update your software to this new package, please be aware of the potential for this alert.
We have thoroughly examined 3 batteries so far which were pulled from Model 3 which received this notice and all were found to be in perfect/healthy condition.
If you get the alert, DON'T panic, at this time we have not identified any cause of serious concern, your battery isn't dead and your vehicle will still operate normally. DO contact us and we will walk you through a reset procedure or send someone to you to perform a reset.