Audio interrupts when listenting to internet radio

When I'm listening to internet radio I have the problem that after some time (I think after about 15-20min) the audio outputs has short hiccups. This repeates all 2 minutes until i restart the station or switch to another station.
Tested with addons "Radio.de", "RauteMusik" and "Rockradio.com". So I do not think its the problem of a single addon.
I'm a total beginner with Kodi, so where could I start with my investiation?

LibreELEC version: v7.90.010 ALPHA
Hardware: SolidRun Cubox TV
Audio output via SPDIF interface

I'm now on LibreELEC 8.0.1 (Kodi 17.1) and still having problems with stuttering audio when playing internet radio stations. Playback from local media on my NAS is fine (audio and video files). But I do not believe there is a problem with my internet connection (50 Mbps, fiber) and Netflix streams are also running fine.
Google finds some similar problems, but none of the discussions has helped me.

My buffer settings in the advancedsettings.xml:

<advancedsettings>
        <cache>
                <buffermode>1</buffermode>
                <memorysize>52428800</memorysize>
                <readfactor>1.0</readfactor>
        </cache>
</advancedsettings>

Debug log file is here.
WAMP

Playback startet at 18:58, audio stuttering began at about 19:30