Please add CEPHtmlEngine as a new mapping application inside Wacom Preferences, it should have same settings that you have for Photoshop. Go to Dan Antonielli website and follow his instructions LINK Multiple Displays Mapping issue (Win only) Scaling performed by:' and choose 'system' in dropdown menu Enable 'override high DPI scaling behaviour.
This happens when your displays have different pixel density. Released of Adobe Photoshop CC2018 (19.1) fixes described issue. Scaling issues on High DPI Displays (Win only) Hopefully Microsoft/Adobe will fix this soon. FAQ Lags after Windows Fall Update and/or CC2018