I may be mistaken but I think this refers to common property within the lot and the fact that, while it must be maintained and repaired by the OC, it must not be damaged by the lot owner. If it is, the lot owner is liable for repairs to it.
In other words, I think this is the opposite of your interpretation.
The OC is usually responsible for repairs to common property except when the lot owner has done something that necessitated the repairs.
For instance, if your ceiling is common property and you drill holes in it, say, to fit downlights, then you have to repair any damage caused as a consequence of those changes.
One other exception to the OC being responsible for common property would be when an owner has been allowed to change common property and has agreed to assume responsibility for maintenance and repairs as part of the by-law allowing them to make the changes.