Apple has sent an internal memo — as noted by MacRumors — that some GPS models of the Apple Watch Series 3— as are showing “edge stripes” on the display. Genius Bar workers and Apple Authorized Service Providers will offer a free fix under the standard one-year warranty.
The problem could come from moisture; Apple advises fixers to have the customer breathe closely on the display to cause humidity and see if the problem appears or worsens. The cellular version of the Series 3 initially had connectivity issues that Apple later fixed through a software update.