Audio messages / speech to text not working on messenger

Hello,

I couldn't get my bot to work on messenger for the past few weeks. I realised that it is actually working if I disable the speech to text feature and send text messages instead. It is really important to me that the messages are actually sent in audio.

Is it a bug or does messenger doesn't support audio messages from bots anymore ? (which would be weird).

If I re-activate audio generated messages, the bot just doesn't "read" the messages (transparent checkmark next to it). It was working perfectly a few months ago but I just came back to it.

Thank you.