The issues were flagged by several users on Reddit. The company added that users have reported that their processing speeds have decreased substantially. The consensus is the problem is being caused by the Intel CPU flag BD PROCHOT, a feature that can be used by any peripheral that's created to throttle the CPU to maintain system temperature at a safe level and avoid overheating.
BD PROCHOT stands for "Bidirectional processor hot".
In a message sent to TechRepublic about the matter, Microsoft said "We are aware of some customers reporting a scenario with their Surface Books were CPU speeds are slowed [and] are quickly working to address via a firmware update".
If you own one of Microsoft's latest Surface devices - the Surface Book 2 or Surface Pro 6 - you'll want to pause Windows Updates for a little while, because Microsoft's latest firmware could absolutely tank your system's performance.
CPU throttling is a technique for preventing overheating from damaging components and is not a bad thing in itself.
The problem is reportedly being caused due to an Intel CPU flag being enabled by mistake.
If you are affected by this throttling problem, sit tight.
You might also have to repeat the same process for your Marvell Bluetooth driver, in case that is also contributing to your overall connectivity issues (as some reports suggest).
This is far from the first problem to have blighted the Surface Book 2 or other devices in the Surface range. So before you disable BD PROCHOT, if you're concerned about the impact, take a moment to familiarize yourself with how hot your Surface Book or Surface Pro 6 feels to the touch now.
Microsoft has become notorious for its botched updates that have introduced bugs as much as they fixed others.