@Yunhua0. I have heard of it, but mostly to do with problems of excess rubbish left by longer stay tenants when they leave. If you are an owner you should contact your strata committee (or strata company if this task is delegated) and ask for an amendment to what would here be called a By- Law. Was the fee in place already or did you miss the notification of a proposed by law change to vote on it? Here they cant just implement a new fee that affects all strata owners.
Laws I have seen here start at 90 days, but this would also align with our rental laws, not STR laws. When I had a strata fully furnished long term rental this by- law was proposed (but defeated). I objected because like you, what expense was the building incurring when tenants move out with a couple of suitcases (and the odd pot plant??).
I agree it doesnt make sense or is fair.