If you have a billing contact defined for a third party and you generate an invoice with an ODT template then the third party company name and the VAT ID are missing from the output. If you drop the billing contact role from the third party contact then all prints fine.
This happen with version 14.0.0.
Edit: I have been able to trace down the problem to function write_file in /home/doymer/dolibarr/htdocs/core/modules/facture/doc/doc_generic_invoice_odt.modules.php. If you have a billing contact then $array_thirdparty is missing the vaues of some keys.