An errata patch for pf has been released for OpenBSD 6.1 today. Details can be found on this page: https://www.openbsd.org/errata61.html
Binary updates for the amd64 and i386 platforms are also available via the syspatch utility. Note that syspatch uses the mirror configured in /etc/installurl, so all mirrors may not have the files yet. OpenBSD 6.0 is not affected.