Do you have to complete a Qantas oneworld RTW redemption 12 months from when it was ticketed?

Hi I was wondering if someone can clear this up for me?
I’ve just got off the phone from Qantas. I had a ticket which ran
TPE -> NRT (Stopover 1 for 3 weeks)
HND -> SYD (Stopover 2 for a month)
SYD -> ZRH (Stopover 3 for a week)
ZRH -> MAD (Land sector)
MAD -> ATH (stopover 4 for 2 weeks)
ATH -> SGN (stopover 5 for a week)
SGN -> SYD (end of actual ticket)
SYD -> TPE (completion of the oneworld ticket back to start point)
This was planned for August through October '21
Given what’s happening in Europe at the moment we decided to push the Europe flights to May '22, and have the Japan trip in October '21.
BUT when I was talking to the service guy at Qantas, he reckoned that I couldnt leave the ticket incomplete till June '21 (when I’d be able to add in the May '22 flights), since a ticket has to be completed within 12 months of the original ticketing date, which in my case was 18th Sept '20. so, I couldn’t add in flights for May '22 since it’s after Sept '21.
In the end I cancelled the whole thing and am going to start again from scratch. But is what he said correct? Thinking about it, I’m not so sure, since when I originally created the ticket I just had SYD - ZRH on it in Sept '21. I then added flights to it with the last one being end of Oct '21. So, I had already broken the 12 months from the ticketing date rule.
I think there is some sort of rule but not quite what he said. I know the whole trip must be completed within 12 months, but is there another constraint on the ticket life?

Many Thanks