In the "CMS Implementation Guide for Quality Reporting Document Architecture Category I and Category III
Eligible Professional Programs and Hospital Quality Reporting (HQR)
Supplementary Implementation Guide for 2016
Version: 1.0 07/08/2015" (often referred to as the 2016 CMS QRDA Combined SIG), CONF:CMS_0043 is worded like this:

SHALL NOT contain [0..0] @nullFlavor (CONF:CMS_0043)

But this constraint was implemented like this:

<sch:assert id="a-1182-28461" test="cda:informationRecipient/cda:intendedRecipient/cda:id[not(@nullFlavor)]">This id SHALL NOT contain [0..0] @nullFlavor (CONF:CMS_0043).</sch:assert>

The wording in the error message is different than in the 2016 CMS QRDA Combined SIG.

The Schematron Assertion needs to be updated with the correct wording.