No problems recently during classes. But the Surface did lose touch with its pen just now when I was looking through today’s annotated slides. I used Hongfei Yang’s suggestion of twisting the back of the pen to deactivate the pen battery and then activate it again. This didn’t work first time (but perhaps I didn’t completely deactivate the battery, or didn’t wait long enough) but worked on the second attempt. Certainly better than restarting the Surface!
I wonder whether moving the pen out of Bluetooth range and then moving it back into range would have a similar effect? I’ll try that next time!