Is it normal that the screen flashes for a long time when refreshing?

Although E-ink display is a very popular type of electronic paper display technology, due to the imaging principle, there are also some defects including screen splash and afterimage issue. After repeatedly turning the page, the ink will remain, which causes the afterimage problem. To deal with that, manufactures designed the full refresh function, however, another issue occurred: the screen will flashes for a while when refreshing fully.