Recently added option

[simoncn]

This is not how MinimServer works. It caches previously scanned files in the added-dates.txt file in addition to caching the file metadata for rescan purposes. If MinimServer finds a file listed in added-dates.txt that has changes (a different last modification date), it reads the metadata changes but does not change the date of the file for "recently added" display.

I think the issue you are seeing is that the audio file has dropped out of the added-dates.txt list because of the limited size of this list and therefore is not identified as a previously added file whose added date should be preserved.