The processing of a large number of music files requires Teufel Streaming system resources. This is normal and comparable to a computer that has multiple programs running at the same time. For most music libraries, this does not pose a problem. For exceptionally large libraries, however, such as those in the terabyte range, the system might be strained to a point where normal streaming is compromised.
Solution - Restart all Teufel Streaming devices and deactivate Chromecast built-in.