Hello,
I use MS Surface Pro and Surface Studio, both with a Surface Pen and both with Windows 10.
Since some days there is no more Pen-drawing possible with the brush tool on both devices (with each a single pen) in Photoshop CC.
When you zoom in once, the pen works like a hand tool but not like a brush.
The pen still works correct in MS Ink, OneNote and even in Illustrator.