Matilda's birth is also registered as HANNING.
The reason that two registrations appear under two surnames is that there are no marriage details on the birth cert. - this would normally indicate that the parents weren't married.
Walter Sydney's, which someone has also uploaded,is interesting. John registered the birth and said that he and Susan were married at Newcastle in 1852. Now considering that this was 1868 and Susan was 28, that would have made her 12 years old. Either his arithmetic was bad or it has been mistranscribed from the original which may have been "1862". If John JEFFERY had died then why didn't John WALTERS marry Susan? Perhaps it was him who was still married to someone else?
Walter's birth cert states previous issue as two males and one female living - these could be Susan JEFFERY (1857), John JEFFERY (1860), and Ebenezer JEFFERY/WALTERS (1862), the one deceased female would be Matilda and perhaps the male is James?
9835/1862, JEFFREY, JAMES (JOHN & SUSAN) FORBES
6620/1863, JEFERY, JAMES (JOHN & SUSAN) BURRANGONG
A Susan DOYLE died in 1944 in Queensland, parents John JEFFERY and Susan HENNING.
There are some people on Ancestry who have details for Susan SHRIMPTON 'marrying' a Patrick LARKIN and her mother is the one above who died in 1944. Perhaps you all need to get your heads together with lots of documentation to sort this lot out.
I can see my GGGrandather's headstone just behind John WALTERS' on the Aus. cemeteries website. Small world.