Billing period description occurs more than once

Error FX-SCH-A-000858 Factur-X

Element 'ram:Description' may occur at maximum 1 times.

Mandatory rule: As long as it is violated, the invoice is invalid and will be rejected by validators.
What is wrong

Within ram:BillingSpecifiedPeriod, ram:Description occurs more than once. This element may appear there no more than once.

What the rule means

The limit ensures that the billing period contains no more than one description and that the XML structure remains unambiguous.

Please keep only one billing period description

ram:Description occurs more than once in ram:BillingSpecifiedPeriod. This billing period may contain no more than one description.

What to do
  1. Find the repeated ram:Description elements in ram:BillingSpecifiedPeriod.
  2. Remove the extra elements so that no more than one remains.
  3. Generate the invoice again and validate it once more.
What it looks like
✗ Triggers the message 
<ram:BillingSpecifiedPeriod>
  <ram:Description>Premier texte</ram:Description>
  <ram:Description>Second texte</ram:Description>
</ram:BillingSpecifiedPeriod>
✓ Correct 
<ram:BillingSpecifiedPeriod>
  <ram:Description>Texte descriptif</ram:Description>
</ram:BillingSpecifiedPeriod>
Technical details

The test counts the direct ram:Description elements within ram:BillingSpecifiedPeriod and requires no more than one.

Where the rule applies

The rule applies to ram:Description within the document-level billing period ram:BillingSpecifiedPeriod.

Context (rule/@context)
/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeSettlement/ ram:BillingSpecifiedPeriod
Test expression (assert/@test)
count(ram:Description)<=1