Free bytes reported by caching api is astronomical

Hello,

Before downloading files/assetbundles to the local cache i'd like to check for free disk space. I found the spacefree property which should return the amount of writable bytes in a long:

https://docs.unity3d.com/ScriptReference/Cache-spaceFree.html

I call it as follows:

Caching.currentCacheForWriting.spaceFree;

This however always returns an astronomical number, on my laptop it sais I have close to a million terrabyte of free storage The spaceOccupied does seem to return the actual number of bytes currently written to the cache.

Can anyone make sense of this?