Unable to convert from & to & for base product &, unable to complete doc.

What causes this issue?

The system could not convert from <GL:base product>base product</> unit
of measure &V1& to <GL:sub-product>sub-product</> unit of measure &V2&.

System Response

Abend. The document cannot be completed.

How to fix this error?

Check your entries.
INCLUDE 'NA_SYSADMIN'

Error message extract from SAP system. Copyright SAP SE.