From the release notes…
v1.28 – 30 January 2026
This release is made only for the Multi RS.
Changes applying to Multi RS:
Fix issue causing incorrect alarm ‘Error Code: #59 - ACIN1 relay test fault’ on some installations
If a Roll back to 1.28 doesn’t solve it then you may have actually have a hardware fault.
Usually its not a good idea to update a working system though, what was your reason for running the recent update?