04-20-2019 07:01 PM
This is a SOLVED issue that I want to report for people suffer from similar trouble.
I have a Thinkpad E480 from 2018 and I had consistently issues with bluetooth devices, when there are two different devices connected at the same time (connected, not paired!). When only one device is connected, e.g. a mouse OR a bluetooth speaker/headset, the devices individually worked perfectly fine. In case two devices were connected at a time, the mouse became very inaccurate (heavy delays and random movement) and the sound suffered from failures and interruptions, ultimetely to stop entirely in some situations.
The bluetooth adapter (Intel 3165) was working fine (appearing in device manager, turning on/off on demand, connecting to the devices quickly), in addition, the driver (v. 22.214.171.124) was updated recently. I also reinstalled the whole bluetooth adapter and paired/unpaired the mentioned bluetooth devices multiple times. Did not fix it. For testing, I had only one mouse, but different bluetooth speakers, and in either combination of mouse/speaker, the issues did occur. BIOS, Windows and all other components were updated recently (April 2019) as well.
I tried to look for similiar cases online, but only found heaps of complains about bluetooth problems regarding broken adapters, connection failures, not recognized bluetooth adapters, or pairing issues with plenty of devices.
Solution: I checked my wifi connection and saw that I was connected to the 2.4 GHz wifi, instead of the 5 GHz wifi. The moment I changed to the 5 GHz wifi, the issues disappeared, while having two bluetooth devices connected. If you struggle from similar issues, check if you have the possibility to connect to a 5 GHz wifi instead or classic cable, leaving most of the trouble behind. Apparently, there is an interference between the 2.4 GHz wifi with bluetooth when having to devices operating at the same time. I am not an expert if also the bluetooth and the wifi adapter are located adjacent to each other, which would be unfortunate. However, a fairly simple work around that is apparently based on hardware not on software issues.
If you cant manoeuvre around with a cable / 5 GHz wifi, maybe changing the 2.4 GHz channel at the router could also ease the issues. I did not try that, yet.