Serviio forgets utf-encoded files

Hello everyone.
I have lots of utf8-encoded files on Linux where I run Serviio.
When I restart Serviio it rescans all the directories, finds such files (with correct names in the log) and shows them to DLNA-clients.
But after some time (probably Serviio-initiated rescan) utf-encoded files disappear from clients, log shows squares in place of national characters and Serviio reports that it failed to find the file in db.
I found that national-encoded (utf) files should be supported by Serviio, but it seems that the feature is broken.
I have lots of utf8-encoded files on Linux where I run Serviio.
When I restart Serviio it rescans all the directories, finds such files (with correct names in the log) and shows them to DLNA-clients.
But after some time (probably Serviio-initiated rescan) utf-encoded files disappear from clients, log shows squares in place of national characters and Serviio reports that it failed to find the file in db.
I found that national-encoded (utf) files should be supported by Serviio, but it seems that the feature is broken.