Is there any UNIX V7 certified operating system?

The Open Brand Register entry for Solaris can still be found on the web site, and still appears in some search results, but presumably it hasn’t been renewed, which is a requirement for products to continue to be listed.

It did appear in the register after the announcement, so its absence isn’t due to a lack of updates — rather, it was added to the list, and then removed again. (This applies to a large number of certified products.)

So there is no currently-registered UNIX V7 certified operating system, but there have been in the past.

As of 30-September-2020, AIX version 7.2 TL5 (or later) on systems using CHRP system architecture with POWER™ processors is now the sole certified implementation of UNIX V7.

As some of the other answers mentioned, previously Oracle Solaris 11.4 was also registered on 10-April-2018, but it appears its registration as a certified UNIX V7 implementation has since been withdrawn. While there has been (to my knowledge) no public explanation of this, we can surmise that Oracle decided that it was not worth their while to pay the renewal fees.