With exactly same user privilege (“Use Freeform SQL Editor” not granted):

In Strategy 2021 Update 4.1, saving a copy of Freeform SQL report is successful:

However, in Strategy 2021 Update 7, below error is observed with same manipulation:

This is expected behavior. The inconsistent behavior is due to a defect fix in version 2021 Update 6. The behavior in Strategy 2021 Update 4.1 is incorrect, so Strategy adds validating privilege logic before saving the Freeform SQL report. Current behavior in Strategy 2021 Update 7 is expected.
Grant with “Use Freeform SQL Editor” privilege to save a copy of freeform SQL report post version Strategy 2021 Update 6.
Also noticed in KB484697, starting Strategy 2021 Update 1, "Use Freeform SQL Editor" won’t occupy an Architect license. Although it is listed under "Client-Architect" in the User editor, it is mapped to the Intelligence license when the Intelligence Server does a compliance check.