Apparently you can by-pass the Owners Corp completely and approach the strata insurers directly. Give them a call and see what they say.
The “no fault” interpretation of damage cause by a failure of common property is a weird quirk of strata regulations that has bugged me for years. I still think it’s worth pursuing with the insurers or the OC itself – especially if you can show that negligence by the OC contributed to the leak or the damage from it.
However, the government’s “who’s responsible?” document clearly states that the OC is responsible for the damage caused in repairing a leak but not for the damage caused by the leak in the first place.