Sorting by “Last Added” no longer works.

Hello, I hope someone can and would like to help me with my problem. For a few months now, Kodi don’t sort my movies correctly. I ALWAYS sort by the most recently added movies. Today I sorted by title as a test and found out, that this no longer works either. Films that start with a letter from the middle of the alphabet come first. I haven’t changed anything in my system or Kodi. What information is needed, that someone can help me? Best regards!