JDK 8u: sun.misc.Version.jdkUpdateVersion() returns wrong result

Starting with 8u262-b01 builds we are seeing test failures in sun/misc/Version/Version.java

jdkVersionInfo: input=1.8.0_262-ea-b01 output=1.8.0_262-b1
JDK version = 1.8.0_262-b1 1.8.0_6-b1
----------System.err:(13/788)----------
java.lang.RuntimeException: Unmatched version: 1.8.0_262-b1 vs 1.8.0_6-b1
        at Version.main(Version.java:47)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
        at java.lang.Thread.run(Thread.java:748)

The issue is that sun.misc.Version.jdkUpdateVersion() returns '6' rather than '262'.

See also:
http://mail.openjdk.java.net/pipermail/jdk8u-dev/2020-May/011642.html