macOS Catalina blueoothd high CPU IOBluetoothBroadcomSchedulerWorkaround issue I've already spent many hours with this and I wasn't able to come up with a solution. Since 10.14.x (I don't remember exactly, currently on 10.15.2) I am have been having this issue (and console flooded with the following message and bluetoothd causes CPU usage of 40-120 %, too) :

bluetoothd     EVENT:  ModeChange
bluetoothd  == IOBluetoothBroadcomSchedulerWorkaround start
bluetoothd  USBProductID 0x7B   USBVendorID 0x5AC
bluetoothd  schedularWorkaroundActive? 0
bluetoothd  active? 0
bluetoothd  == IOBluetoothBroadcomSchedulerWorkaround end
bluetoothd     EVENT:  ModeChange
bluetoothd  Apple HID device count: 0
bluetoothd  updateAppleHIDConnectionIntervals - connectedAppleDevices 0
bluetoothd  updateAppleHIDConnectionIntervals - twoSniffAttemptDeviceCount 0
bluetoothd  updateAppleHIDConnectionIntervals - connectedSCODeviceCount 0
bluetoothd  Dont enable MSS for this device Microsoft Sculpt Comfort Mouse
bluetoothd  == IOBluetoothBroadcomSchedulerWorkaround end


Happens with a Microsoft Sculpt Comfort Mouse and two different (Logitech) mouses, too. Any ideas what I could try? I've already tried deleting plists, NVRAM, reseting SMC, booting into Safe Mode, reseting BT setting in macOS… Thanks!

More details: Machine specs are: MBP 13" 2018 (2.3/16/512). 
Apart from this, bluetooth connection drops randomly and the issue occurs both with Wi-Fi on and off and the USB-C dock connnected and disconnected.
I've found a workaround: I've figured out MSS probably means Master-Slave-Switch. That didn't suffice to fix the issue. But disabling sniff mode resolves the issue. It seems that some energy management code doesn't work properly. 
The cause of the issue traced down: Apple has a bug within BT3.0 Stack. This issue is not happening with anything BT4.0+.