I've seen it in other non snow biking things, the powder coat bake is too hot and too long. Those sides are likely 5052 I'm betting and the riveted rails probably are too which is sh1tty aluminum for this application.
Actually you can. But not with the web that is used. Weakens the structure in all the wrong places. Improving TS web and frame is (lighter and stronger) is pretty basic knowledge if you are a structural engineer that is used to working with steel and aluminium in motorsports especially. If you also take into account switching to high strength steel and higher aluminium grades, we can really start talking about improving what from the beginning was a brilliant start/idéa. But improving the idea can make it so much stronger and lighter.