Erte, I agree with Kaindub. Treat the unit as never having been sold or alternatively, sold many times. The liability is attached to the unit regardless of owner or sale.
Jimmy suggests that a thorough strata records search be undertaken by the purchaser. I agree. But what happens when either the strata records are missing or shed little or no light on this large body of work? To that Jimmy says: “If the vendor deliberately misled them, then the new owner can sue”. I would go further. Deliberate misleading is a definite no-no, but so is the vendor not sharing all the information at his disposal which would influence a sale.
As mentioned, the opinions expressed in this forum are products of experiences of owners or residents in strata schemes. They are personal opinions of layfolk and not legal advice.