I found recently, that between May 20 and 27 my EX4100 is stopped to index new files. As result, Android app doesn’t see this files, but I could see it in Windows explorer. Also about this time my Plex application also stop to found new video files automatically (but I could manually re-scan filesystem, and it solved issue until new video file.
I guess it’d be related to recently automatically installed new update of firmware 5.13.115. Or maybe I missed something and search by default is disabled?