Responsive mode in prototypes are broken

Why is the responsive mode in the prototype preview so broken? When you create a page with components and layers and set them to fill mode, everything fits to 100% width or height in the design editor. This reflects typical development as expected.

However, this doesn’t work in the prototype preview. When I set the prototype to responsive, sometimes it works, sometimes it doesn’t. For instance, I have a grid with cells. Those cells are set to fill. (In fact, everything in every layer is set this way). But when the prototype renders it breaks. Those cells sometimes are 100% the available area, other times they are set to their original rendered size from the frame.

For example, the cells are set to fill and happen to measure at around 200px wide because the main container (frame) fits all the content this way in design mode. But when it goes into the prototype preview with responsive mode, sometimes those cells take up the width appropriately, other times they revert back to what they are calculated at from the original main container.

Design: [ cell = fill ] (equates to ~200px or so)
Prototype: [cell = fill ] (may be 100% or may be ~200px)

Another issue, I get random fragmented lines on those cells that are not in the original styling. An artificial border that shouldn’t exist.