I think the version 2.2 of xsd file is wrong in general as the 2.2 was released in 2017 but in your file there is other date: "@(#)persistence_2_1.xsd 2.1 February 8, 2013" (2013 is release year of 2.1).

So for the sanity the versions of files for 2.1 and 2.2 should be compared to the official ones released by oracle probably: http://www.oracle.com/webfolder/technetwork/jsc/xml/ns/persistence/index.html

Only the version change inside the text may be insufficient for you xsd for version 2.2.