No audio reel when shared to grid

Hello,

 This is a recent issue. My reels play fine in preview but when they are shared to my grid the audio is silent (for me and my followers) 

Tried on all 4 of my devices some of which have different android/Instagram versions but it's the same result.. no audio when it gets to my grid. 

I have tried so many things,  different videos, different audios, changing anything which seems relevant and some settings which are really obscure but no luck. 

 If it happened on just one device I could probably accept it is something I can change but as it happens on all devices with old & new versions of software I am starting to worry the problem is to do with my account  somewhere "higher up" in the depth of Instagram itself. I have raised the issue with them but no feedback yet. 

Any suggestions please?