I can confirm this is also a problem in Vivid. I'm not using the same mouse but symptoms are pretty much the same(except the BT icon doesn't always disappear) . I've updated the kernel to 3.19.2 (for other reasons - HDMI audio was broken) but that didn't help the bluetooth issue (I'm assuming it's a bluez problem rather than the kernel itself). Happy to help troubleshoot if someone can guide trough the relevant processes to monitor.
I can confirm this is also a problem in Vivid. I'm not using the same mouse but symptoms are pretty much the same(except the BT icon doesn't always disappear) . I've updated the kernel to 3.19.2 (for other reasons - HDMI audio was broken) but that didn't help the bluetooth issue (I'm assuming it's a bluez problem rather than the kernel itself). Happy to help troubleshoot if someone can guide trough the relevant processes to monitor.