Webservices - BIS (Supplier Invoice) - Zero Value VAT Ignored

Hi, an issue with v12.

Through webservices we have encountered an issue where the VAT field (Tax Amount) is ignored when the value of the field is zero.

This is causing X3 to recalculate the line VAT (incorrectly), instead of accepting the zero value.

This was working in v11 and previous versions.

Looks like a bug, but any thoughts or guidance is welcome.