PB layout deformed, vertically stretched

Hello there, I’ve been happily using PB for a while. The only issue is that at some point the PB layout appeared completely deformed, with each row showing a long vertical stretch. Functionality is perfect and all widgets work, but every post or page where PB is active shows an out-sized height, regardless of the number of widgets. So, it is necessary to scroll up and down the page to manage widgets, and finally save. Thanks for your help!