An issue has been introduced on upgrade in MYOB Acumatica to version 2026.1.2. Previously on Version 2025.2 there was a bug on conversion where the GL Account on the discount line was removed, and this has been fixed on this upgrade - however the new and serious tax calc issue has been introduced. We are not sure if related.
Casting the net to see if any Acumatica sites have experienced this as we are in one of the earlier MYOB upgrade cohorts and are the first partner to report it. It can be replicated on an MYOB Demo site.
Having the tax engine not calculating is not great - note that MYOB do have a tax layer for our region. Knowing if Acumatica users encountered this on a previous version would be great to know as MYOB versions are a little behind.
Workarounds such as removing the tax line from the taxes tab and re-adding are cumbersome and risky for the client who processes very high volumes of transactions.
The issue only occurs if a Discount Line is present on the Quote.