stalePeriod clarification

i used to think that maxAgeCacheObject, which was i guess replaced with stalePeriod worked like so:
we download file -> mark some expiry date for it -> when it's expired we redownload it

with current docs it seems that's not the case
https://github.com/Baseflow/flutter_cache_manager/blob/46f0a0466d62350b48a520a5561fd59e0c546dda/flutter_cache_manager/lib/src/cache_manager.dart#L32-L33

so if i have stalePeriod that equals to 1 day and user opens my app each 12 hours, for instance, and the file is being reused, my cache will never be invalidated? if that's true, how do i change this?