[General Topics] Elements1984:
I am sorry to read your two messages and find out that the problem still remains.

Actually, yesterday I came across a thread in some forum where some people experienced the same thing where they could fix the problem only if they switched into the handset microphone and then back to the bluetooth (or something like that), I will have to look for this thread again and share it with you. But if I am not wrong, there was no permanent fix found at the end of that conversation, maybe a solution was found on another forum though. But with all the new information you provided through the last days of experimenting new things, we have more symptoms in place to try exploring topics that people may have experienced about some but not all of the problems you have, either because these people did not notice the whole extent of the bug or because their usage was different than yours, for example people using the bluetooth of their car audio might be used to shout if they wish to be heard when using their old phone connected by bluetooth and that's why getting a new phone will not make them realize the difference.

Anyway, I have been thinking of a serious scenario last night and I wanted to ask you to check this to make sure we are dealing with bad settings rather than a rom bug, which then will be a totally different approach to fix this problem:

If you can, try to make a bad phone call where the microphone isn't loud (which means don't use the fix you found), now I want you to leave the room wearing the bluetooth headset and let the phone inside the room or inside a closet, try closing the door but stay in range of the bluetooth signal.

Why? Because it could be that the low volume during your calls is picked up by your handset microphone (internal mic of your phone) and that you just didn't know it, the bluetooth mic might work just fine with skype, voice notes and others but not with voice calls.

If this is what is happenning, then I guess it's a bug in the stock rom which CM might have fixed, basically this would mean that when making calls using the bluetooth headset, you will be using the earphones to hear them but you will be speaking on the device microphone which didn't switch to the bluetooth mic for some reason (a bug) until you have to use this new trick that you mentioned in your last message which forces the bluetooth microphone to start.

If you can confirm whether this theory is right or wrong, we can try to target our efforts on the the right problem: is it the mixer settings? Or is it simply that the microphone doesn't start and you're still using the internal mic?

If you reply fast enough, I might be able to reply again in few hours, otherwise I'll get back to you tomorrow ;)

Clicking on the thank you button is the best way to thank me :)

Edit:

Here is the answer I found last night, but it's not a permanent fix and it's the reason why I didn't share it. But it's basically the same as what you found:

"I had a similar problem with my G3. I would call people and they were unable to hear me on the other end. I could hear them fine. ***

I experience this also on my G3 and disabling "OK Google" didn't resolve it.

Whenever this occurs, I put the call briefly on speakerphone and then back off again. Then, the caller is able to hear me clearly."