In short: The way it looks, has the device (just like the YATOUR, xcarlink2 and anycar) a problem with high bitrate MP3s.
When using encoder LAME in "-V2 --vbr-old --strictly-enforce-ISO", it works. About 256kbps will not be playable from the beginning - a few seconds then missing and the music starts with a click on.
The decoder probably seems to have too small a buffer and therefore comes under special circumstances to a halt. For example, if there is a peak bit rate at the beginning of the song. Etc. Who MP3 from Youtube used should not have any problems.
WMA, incidentally played without hesitation, even at maximum bit rate. So I can only come from a lack of quality control in the design of the device.
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Addendum 03.11.2015:
Although the random playback functions (because my radio supports it), but has a few title problems: it will jump to the next title, but play nothing. The only thing that helps is the radio off and turning on again. From quality goods here can really be no question.