Dear Support.
This is just for the info which I have experienced while using the version de_538h_2019-12-10 there are approximately 35 files with no vocals/voice which is making trouble when processing the data. The list of files is
clips/common_voice_de_17486238.mp3
clips/common_voice_de_18235786.mp3
clips/common_voice_de_18235793.mp3
clips/common_voice_de_18235796.mp3
clips/common_voice_de_18235804.mp3
clips/common_voice_de_18235807.mp3
clips/common_voice_de_18235808.mp3
clips/common_voice_de_18235810.mp3
clips/common_voice_de_18235811.mp3
clips/common_voice_de_18235812.mp3
clips/common_voice_de_18235813.mp3
clips/common_voice_de_18235814.mp3
clips/common_voice_de_18235815.mp3
clips/common_voice_de_18235816.mp3
clips/common_voice_de_18235817.mp3
clips/common_voice_de_18235818.mp3
clips/common_voice_de_18235819.mp3
clips/common_voice_de_18235820.mp3
clips/common_voice_de_18235821.mp3
clips/common_voice_de_18235822.mp3
clips/common_voice_de_18235823.mp3
clips/common_voice_de_18235824.mp3
clips/common_voice_de_18235825.mp3
clips/common_voice_de_18235826.mp3
clips/common_voice_de_18235827.mp3
clips/common_voice_de_19411969.mp3
clips/common_voice_de_19411970.mp3
clips/common_voice_de_19411971.mp3
clips/common_voice_de_19411972.mp3
clips/common_voice_de_19411973.mp3
clips/common_voice_de_19411979.mp3
clips/common_voice_de_19411980.mp3
clips/common_voice_de_19411981.mp3
clips/common_voice_de_19411982.mp3
clips/common_voice_de_19411983.mp3
It may help others and you as well and safe time. Maybe while extracting it is only at my end. But I cross-checked twice at least and same findings discovered by me.