The workaround I now use is to modify the cp -a command in /etc/ppp/ip-up.d/0000usepeerdns to look like this:
cp -a "$REALRESOLVCONF" "$REALRESOLVCONF.pppd-backup.$PPP_IFACE" || { rm -f "$REALRESOLVCONF.pppd-backup.$PPP_IFACE" "$REALRESOLVCONF.tmp" exit 1 }
The workaround I now use is to modify the cp -a command in /etc/ppp/ ip-up.d/ 0000usepeerdns to look like this:
cp -a "$REALRESOLVCONF" "$REALRESOLVCON F.pppd- backup. $PPP_IFACE" || { F.pppd- backup. $PPP_IFACE" "$REALRESOLVCON F.tmp"
rm -f "$REALRESOLVCON
exit 1
}