In short: it seems that audios in the 3gp format are not being shared.
For my greek language deck I have recorded about 600 words with the edit note interface.
They happen to be recorded in the 3gp audio format: it works perfectly on my desktop and android versions but does not work in Anki Web. Crucially, they seem to not be counted as audio in the shared version:

The shared deck interface shows only the 3500 mp3s not counting the 600 3gp
This is the interface where I recorded all the files:
Now, I could find a cli tool and batch-convert all the files into mp3; but it seems that actually Anki should support 3gp end-to-end. Currently it allows recording but not sharing. A consistent approach would include also sharing, and Web.
