Time when the document was issued.The issue time must have granularity of seconds, and include time zone information

Namespace
cbc urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2
Data type
Time
Rules
Identifier/Error message Flag
PEPPOL-T006-R007
[PEPPOL-T006-R007] IssueTime MUST have a granularity of seconds
fatal