For a start, mere ownership of something is never enough to establish liability. Negligence is usually needed too.
How may times do you need to be told to check your appliance hoses before failure to do so is negligence?
But I’m going to vary my response slightly and come at it from another direction.
It’s the lot owner’s responsibility but it seems the damage to common property will be covered by strata insurance. However, where it isn’t covered, then the lot owner is liable.
When would strata insurance NOT cover this damage? When there is an excess on the policy and it only covers part of the cost. See this Q&A on Lookupstrata.