I can also confirm the intermittent z-wave issues are due to the current firmware, v1.59.0-1.13.2
My solution: I contacted August support and told them all the troubleshooting steps taken (i.e., changing the battery, factory resetting, etc.) and linked them to this thread, specifically citing that other people had success by downgrading. They immediately followed up (same day) and agreed to push the firmware to my device. Once I opened the August app, there was an “update” available, which was really a downgrade to v1.59.0-1.8.15.
Future readers: if you end up going down this route, I suggest not using the August app to avoid accidental updates. Personally, I will not be updating until August fixes the issue on their end.
So far, I’ve gone 3 consecutive days without any issues.
For reference, this was the response from August support:
Thanks for reaching out to us!
We appreciate all of the troubleshooting steps you have already performed. We would be more than happy to revert your firmware: 1.59.0-1.13.2 to the previous firmware version 1.59.0-1.8.15 to restore your Z-wave capabilities. When standing within Bluetooth range of your lock, the previous firmware version will be installed.
Please let us know if you have any further questions or concerns.