Debt to GDP in China is pretty unsustainable. Asking for a cause is hard and property markets are generally less liquid so rises and falls tend to be more drawn out, but it's probably going to be Chinese banks getting hit by bad loans and the government propping them up. The Chinese stock market isn't as frothy as it was a couple years ago, but the larger Chinese economy still relies on property backed debt for business expansion.

While I agree that property in places like Canada aren't overleveraged, demographics (baby boomers) are masking the true picture because a very large percentage of the population is relying on home equity to sustain their standard of living into retirement and there is a non-trival amount of "off-book" leverage in the form of mom and pops lending a couple hundred grand to their kids to get the 5% or 10% down that you're legally required and the kids are ploughing the majority of their income into their mortgage just before having to support the healthcare system as mom and pops retire and start to really hit it. With less of paycheque available mortgages are going to get strained, even if interest rates stay this low for the next couple decades.

This is all kinda handwavy, I'm not really sure how, but I'm sure that what we have now is unsustainable. I might be wrong about a hard crash, they could try to inflate their way out of the debt / inflated assets, but we're definitely not going to see a good amount of growth in the stock market for the next 7 years or longer if there is no pullback.