[T1] Why Does the E-Paper Screen Flash/Invert?

The E-Paper flickering or appearing to temporarily invert is normal part of e-paper technology operation.  The e-paper screen refreshes from time to time (approximately every 30 seconds) and during certain actions taken by the user.  This is normal behavior and related to how the technology functions. 

E-paper technology is unique in order to achieve the high contrast and paper like appearance.  Internally, a collection of black and white balls are moved which change the overall appearance of the display.  The refreshing action ensures that these balls are aligned correctly based on the content being displayed 

You can read more about the process here - https://www.visionect.com/blog/why-epaper-blinks/