Notification Panel drops down and disturbs call

[Ryverdeep]

Of late nearly every time I make a call I have a problem with the notification panel. For some reason it seems to drop down seconds after the call has begun and inexplicably, the person I am speaking to can no longer hear me. I cannot understand how this is even possible. After I clear the panel sometimes I can be heard. Other times I have to shake the phone and push buttons.
Does anyone have any idea what is causing this and how it can be fixed.

[Hampus]

Hi,

Do you see when the notification panel drops down or does this happen when you put the phone next to your ear?

[Ryverdeep]

It happens after I've put the phone to my ear. Once I've realized whoever is on the other end can't hear me, I pull the phone away and then after the screen turns back on I see the panel has dropped.

[Hampus]

Do you experience the same behaviour if you boot the phone into safe mode? 

[Ryverdeep]

I haven't tried safe mode

[Ryverdeep]

After trying safe mode several times over the last week I haven't had the problem.

[santhire]

Then it must be a bug with third party app

[Ryverdeep]

How can I find out which app is causing this problem.

[Hampus]

Unfortunately, it can be a bit tricky to find out which app that cause this. You said that you clear the panel and then you can be heard, do you have any specific notifications when this happens? For example if you have some kind of call recorder installed that you see in the notification field etc.

[Ryverdeep]

What appears are existing notifications and sometimes the panel is clean. Clearing the panel works some of the time, I find that pressing the mute or speaker button helps to restore sound. There is no recording app.