When you share a folder which is also used by other app like bittorrent client to download data, then i suspect that Fopnu (and DarkMX) keeps re-hashing the incomplete file, causing waste of a disk IO and CPU spikes.

I know that the workaround may be to set bittorrent client to use temporary non-shared folder or append "incomplete" extension (but Fopnu and DarkMX fails to support file/folder name blocklist?).

Idea to solve this:
App would hash the file (include it into the library) only
A) after lets say 7 days (user defined) since last modify/update time of the file
B) if the hash changed less than 2 (user defined) times in last 7 (user defined) days
C) allow user disabling or delaying seemingly live analyzer of a library file changes