I spotted this on a mobile when I turned it to portrait.
My page has a bunch of text and images then the grid on the bottom of the page. My grid has minimum height, so turning portrait might mean the lower rows are off the screen and a screen (not grid) scroll up needed to show the rest of the grid.
ISSUE: I load the screen portrait and due to the height of my top section, I can only see the top row of my grid. When I do a page scroll (not grid scroll), the rows that were off screen are blank, unless I refresh or even do a grid scroll then the rows appear.
I'll try and get a demo up tomorrow.