They just responded to me around 10 minutes ago as follows:
"Thank you for contacting the Qantas Frequent Flyer Service Centre.
We apologise for the delayed response and we appreciate your patience on this matter.
As we've check your account, the reason why the %20 Bonus Qantas Points is not reflecting on your account after transferring xxxx Qantas Points from AMEX is that the transfer was made 1st July 2019, not 30th of June."
Me, without checking my account (or this thread!) immediately responded that it was 6/30 here which is 7/1 in Australia and attached my Amex screenshot. Only after that did I read the additional responses here and see that people had the points post so I checked my account and b"h mine did too! So I wrote a follow up email to disregard the previous one as points had posted.