dBpoweramp cannot convert some files encoded by "lavc"

[dftf]

I have a number of MP3 files which the "Audio Properties" tab in dBpoweramp says are encoded by "Lavc57.48"

Some convert successfully, but others come back as "Error decoding MP3 data stream, is corrupt?"

As a workaround I can open them all successfully in Nero WaveEditor, and then do File > Save As to export to WAV or FLAC from there

Any reason why some work and others not?

Example:
Lavc-Example.PNG

[Spoon]

These mp3 files must not follow the mp3 standard.