Here is the dojo to reproduce. In this dojo I've created imitation of data, that coming from server in our case. The main idea is to have a grid with lazy loading - it has 10 groups (page 1) and after scrolling down it loads 10 more groups (page 2) and etc.
After scrolling down, data from the last group is updated with some data, that is not belongs to it. Please see 'Issue1.png' attached.
Groups from the first page are duplicated after scrolling down. For example, there is a group named 'C3'. After scrolling down, it is duplicated once again. Please see 'Issue2.png' attached. New groups are placed after these duplications. By the way, as groups from the 1st page are duplicated, there is more than 20 groups is shown, but the counted at the bottom of the grid says that '20 of 137' elements are show.
So it would be great, if you could fix that. Or even provide temporary fix for us.