Specifying anything other than default via in ipv*route causes pvestatd to throw an error and not boot:
Etcnet reader: /etc/net/ifaces/vmbr0/ipv4route: unrecognized line "classified" table "classified" via "classified" at /usr/share/perl5/PVE/INotifyEtcnetOverride.pm line 614, <$fh> line 2.
Compilation failed in require at /usr/bin/pvestatd line 6.
BEGIN failed--compilation aborted at /usr/bin/pvestatd line 6

A temporary solution to ignore such entries and use comments:
/usr/share/perl5/PVE/INotifyEtcnetOverride.pm

#<----->} else {
#<----->    die  "Etcnet reader: $path: unrecognized line $line";