I recently had a page stop working in Mobile view. Further investigation lead me to find the mktoMobileHide code had been added to my page and I had no clue how or what added it. At first I thought it was the "Validate Mobile Version" in the LP editor. Upon further investigation I found out one of my co-workers had looked at the page in the LP editor, clicked on the Mobile tab to see it there and approved Marketo to make a Mobile version of the page, which blanked out the entire page by inserting the code.
For people who are hit with the mktoMobileHide issue, who have scripted their own mobile friendly CSS and HTML, go into the LP editor and turn off the Mobile Version and see if that works.