Unusual crosshairs icon with Wacom pen

When using my Intuos pen, occasionally the brush cursor turns to a strange crosshair, shown in my attachment. I haven't seen this crosshair in Photoshop, but Wacom says cursors only come from the OS or an app. If I move the mouse, it turns back to the normal brush cursor. If I again move the pen on the tablet, the strange cursor reappears. 

Does anyone know what Photoshop cursor this is? Thanks.