I primarily use subsonic via the web interface at work to stream my music from my external hard drive at home.
Back in 4.7, I would remotely download files to my home hard drive while at work and, using the subsonic web interface, would simply "Refresh" the media folder they were downloaded to before they were immediately scanned, recognized and able to be played.
Then something changed once I upgraded to 4.8. When following the same process, the subfolder the files were downloaded in would immediately be listed the same as before, but when diving into it, none of the actual files would be displayed or sometimes only the very first file of many (10-20 or so) would be displayed. The only way I could get subsonic to see and play these newly downloaded files was to preform a full "Scan media folders now" scan which resulted in thousands and thousands of files in multiple folders being rescanned, when really all I wanted was the single new subfolder located in a single media folder to be rescanned.
I was hoping this might be fixed in 4.9 but it seems to be acting the same way. What does the "refresh" button actually do if it's not scanning the new subfolders and files in that media folder? It used to work seamlessly which is the only reason I bring it up, I love Subsonic other than that!