Upfront is a great new page building tool. I've enjoyed working with it so far, however I've noticed a weird behavior with the responsive mode. When I enable responsive mode and make changes to the big tablet, tablet and mobile views (e.g. reordering blocks, changing height of blocks) the changes save the first time without issue. However if I leave responsive mode and go back into responsive mode later to enter a second round of changes, it reverts back to its original state as if the first round of changes never happened. This happens regardless of whether I simply leave responsive mode or leave Upfront all together.
Don't need an immediate fix to my site. Was just testing out the new Upfront tool and wanted provide feedback in case this helped with development. Thanks.