Not determined by the type of mp3 file

Sorry for my English. I hope the screenshots explain better than my words ))

Elgg.1.7.10 (actually also 1.7.9)

I uploaded mp3.

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I choosed mp3 file

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But the uploaded mp3 file is not determined as Audio and marked as General

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Also on the File page i can not listen it with zaudio plugin. Just I can download it

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With files of other formats it works

Please, need your help!