When I use the monitor with AMA function , its leaves a shade when scrolling the page, when turning OFF the AMA , the shadows issue doesn't happened. Is there any advice you can provide?

That is Overdrive/Response Time Compensation (RTC) function in RL/XL series. This technology is based on applying an over-voltage to the liquid crystals to motivate them into their orientation faster. We will usually quote a "grey to grey" (G2G) response time figure on displays using this technology since they are normally the fastest transitions available.