The decimal separator is a comma
Amounts must use the dot as their decimal separator.
A financial field: the expected value is computed and offered, never written into the document — the correction is the issuer's to make. Test your invoice to find out whether it is affected.
Why this error happens
A direct consequence of locale-sensitive formatting at serialisation time. The amount carried is correct: only the way it is written is not — and the invoice will be rejected by every platform all the same.
How to fix it
Fix the serialisation in the system that produces the invoice. Factlint returns the expected value but does not write it: the rule is that we touch no financial field, even when the correction looks neutral. A safeguard with an exception stops being one, and that is the first thing a third party would challenge about the integrity of the document.
financial_field_policy
XML correction example
1200,00
1200.00