Based on a Debian patch by Urs Fleisch <urs.fleisch@gmail.com>
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=680915
Index: id3lib-3.8.3/src/io_helpers.cpp
===================================================================
--- id3lib-3.8.3.orig/src/io_helpers.cpp
+++ id3lib-3.8.3/src/io_helpers.cpp
@@ -364,10 +364,17 @@ size_t io::writeUnicodeText(ID3_Writer&
     unicode_t BOM = 0xFEFF;
     writer.writeChars((const unsigned char*) &BOM, 2);
     unsigned char *pdata = (unsigned char *) data.c_str();
+    unicode_t lastCh = BOM;
     for (size_t i = 0; i < size; i += 2)
     {
       unicode_t ch = (pdata[i] << 8) | pdata[i+1];
+      if (lastCh == 0 && ch != BOM)
+      {
+        // Last character was NULL, so start next string with BOM.
+        writer.writeChars((const unsigned char*) &BOM, 2);
+      }
       writer.writeChars((const unsigned char*) &ch, 2);
+      lastCh = ch;
     }
   }
   return writer.getCur() - beg;