This article describes an issue that occurs on a Windows Server 2012 R2-based Remote Desktop Session Host (RD Session Host) server. You can fix this issue by using the update rollup in this article.
When you search for certain German filenames in File Explorer, the results are hidden when the input reaches a point in wordbreaker. Therefore, even if you have all full partial matching conditions satisfied, the correct information isn't shown.
This issue occurs because of a bug in the internal matching logic implemented by German wordbreaker.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.