Hi Adrien,
you are very welcome!
you are not going to believe this but despite all the information I have provided to Apple regarding this issue and then supposedly following this post, they have just come back to me this morning with the following:
Advisors and customers are reporting successfully resolving the issue by un-pairing and forgetting the headphones from the iOS device, then re-pairing them.
Please can you give this a try and let me know if it works.
I'm just estonished that they are now asking me to perform basic troubleshooting steps which is on their website, its as though they have completely disregarded all the information I have given to them from the outset, I have pretty much done stuff they should be doing regarding the research and they have Coke back with this, I'm appalled with the level of support regarding this case considering in the last my experience has always left me coming away happy, that being problems with my iPhone, Mac or Apple Watch. I just didnt expect this from Apple.
Anyway on another note, I have been doing tests of my own and just as well, I have been running IOS 9.3 on my phone for a few weeks now and the outcome is good as it appears to contain a permanent fix for the beats disconnecting issue for beats running firmware 1.1.12, I don't believe that this is something Apple have done purposely to fix out issue directly, I think it was an issue which they had caused in 9.2 with something related and they have fixed this and it so happens to have fixed the beats wireless issue at the same time.
I Believe 9.3 will be released very soon but if you can wait that long you can sign up for the public beta and install it that way, if you read further back on this thread you will find my instructions and further information on how to do this.
I hope this helps!
thanks,
Jason