Issue with convert, does not create target dir for ffmpeg

Hello,

I am trying to use convert to convert from flac to aac.
I am confuser because the copy of lossless files work fine, but creation of the target dir for ffmpeg conversion is not perform.

ffmpeg fails with the following:

[out#0/ipod @ 0x600000270840] Error opening output /Users/mremond/Music/Beets-iPod/Black Pumas/Chronicles of a Diamond/09 Gemini Sun.m4a: No such file or directory
Error opening output file /Users/mremond/Music/Beets-iPod/Black Pumas/Chronicles of a Diamond/09 Gemini Sun.m4a.
Error opening output files: No such file or directory

Any idea ?

Thanks !