Install this new driver, restarting when prompted (or manually after if not).In the list should be an update for ‘ Broadcom – System – 12:00:00 AM – 12.0.1.874’, one minor version increment from 12.0.1.873.Open ‘Show optional updates’ for additional updates.Go to Settings → Update & Security → Windows Update and click the Check for Updates button.There’s a better driver which Windows won’t install automatically but should make available as an optional update in Windows Update at some point.
The Bluetooth drivers that come with Boot Camp WindowsSupport are version 12.0.1.873. Since this is only an issue in Windows, it must be a driver issue. Try disconnecting other BLE devices and trying again. View → Sort by connection, then open the Bluetooth enumerator and BLE devices are grouped separately to non-BLE devices. You can find out if a device is a regular Bluetooth peripheral or a Low Energy peripheral in Device Manager. This isn’t a problem in macOS, only Windows. When more than one BLE device is connected to your Mac while in Windows, this causes all BLE devices to interfere with each other, causing lag and stuttering.