There is a whale trying to get more coins, forcing sell orders lower but doesn't want their coins sold. They moved there sell wall up from 1210 to 1400, as soon as the price gets close they will remove the sell order again and place it higher. Watch!
Is there a name for such practice?
You force the build of up of sales below the sell wall and when said whale is ready to buy up he gets a lot more Gulden. Standard trading tactics, it's a good thing, if the sales were thin it means they want to sell.