Medion Spotify Connect compatible device stops playing

[Joerch]

Plan

Premium

Country

GER

Device / OS

Motorola G5S Plus (Android 8.1.0 / Spotify 8.5.36.747)

Motorola G6 (Android 9 / Spotify 8.5.36.747)

both connected via W-Lan (doesn't matter if it's 2,4 or 5 GHz)

Desktop (Win 10 Home 1909 / Spotify 1.1.22.633.g1bab253a)

Connect-Device:

Medion P85035 MD 87090 (Firmware ir-mmi-FS2026-0500-0097_V2.10.13.EX67604-2RC10)

connected via ethernet

My Question or Issue

When playing songs from list "recently played", "your library" or "last search results" on above connect compatible device, only first song is played and then playback is stopped or first song is in loop (repeat option isn't checked). This is reproducable since the last 2-3 month and of course annoying.

E.g. spotify:album:5gheyhP3zMgMhigeOXQ0hH (and many more)

A not stable workaround is to perform a new search for album and play from the search result.

Other connect devices in same ethernet doesn't have this problem.

I tried a clean resinstall on devices and also sent Medion device twice to manufacturer, who say's that device is ok.

Battery saving options are disabled on Android devices.

Also tried to force NAT2-type in router configuration, which shouldn't be necessary cause other devices works.

Problem still exists.