On Vaucluse units comment, I saw a similar thing happen with houses in Bondi Junction. The heat map for all surrounding suburbs was purple (median sale over $1.2m) yet Bondi Junction was red...median over $1m. The heat map now shows all purple. Bondi Junction house prices up 14% in 12 months.
If the house (or unit) is surrounded by suburbs with more expensive houses (or units) sale prices in the cheaper area have a habit of rising closer to neighbouring suburb prices.
I'd be watching houses in Surry Hills and Redfern which are only orange (median over $800k) and houses in Kingsford (red over $1m) as the next areas to rise in price.
Wollstonecraft in the north (houses) is another area that has lagged surrounding suburbs on the heat map.