This change occurred with the 3.7.4 RPM used by both wolverine and rawhide. There's a program called checkpc which, among other things, forces permissions for certain files back to values it "knows". Well, for /var/spool/lpd/{printer}/filter, a symlink to /usr/libexec/master-filter, checkpc wants the perms for this file to be 0600. Unfortunately, lpd wants (*needs*) the permissions to be 700, since it needs to execute that file. So, when you start lpd, checkpc bitches about perms on .../filter being 711, not 600, and sets them to 600. Then lpd comes along and bitches that the .../filter does not have execute permission. In this little battle of wills, lpd is right, since if /usr/libexec/master- filter doesn't have execute perms, nothing gets spooled or printed.
this has been fixed in at least LPRng-3.7.4-22 and later.