Building has concrete cancer....just how bad is it?

Apologies if this is the wrong subreddit to ask this. I'm looking at buying my first home in Sydney. Budget is towards the lower end so alot of the properties I'm looking at have some sort of an issue. I absolutely love this apartment interior wise but I have concerns regarding the building itself. Evidently has concrete cancer which (appears to) have been patched up? Just how bad is it? I'm trying to figure out if this is a straight out nope...or if there is a price where it would be a decent buy. Not that it matters since it all falls under strata but the apartment I'm looking at is the one with the 'rose court' on the balcony - by no means worst affected. Any advice or input would be greatly appreciated!!