It sounds like it has an accumulator to store pressurized oil for pre-start unfeathering. The accumulator would normally be dumped when yoiu take the prop level out of feather.

Some light twins have the accumulator as an option (a flight school would want that option, a private owner might not). This can create confusion when folks learn on one airplane, then go fly another of the same type which did or did not come with the option.

But to be honest...you really should get educated on that sort of system BEFORE you fly a twin.