Don't want to nag to much but is there any news regarding this? Buster is planned to release pretty soon (<2 weeks) and iptables is quite a important package, IMO. Maybe it went under my radar but I saw no unblock request on d.o release list.
For now I just used update-alternative to use the legacy variants, which work fine here, but if my understanding is correct then this package (version?) could be thrown out of Buster if it still has RC bug so close to the planned release, I mean iptables may be an exception as it's quite relevant and still used by a lot but still.