March 2021: 2.8% in one month — the fastest move since 1988

Of that 2.8%, roughly two-thirds was new-listing scarcity (listings were 25% below trend) and one-third was demand pull (cash rate at 0.10%, $200bn of household savings accumulated through 2020 lockdowns). It was not credit-fuelled speculation — household debt-to-income actually fell slightly in the quarter.

Bubbles don't have 25% listing deficits. Bubbles have stretched leverage and excess supply. March 2021 had neither.