Pardon, but I'm struggling to connect the dots here.
As you describe the event, it seems like a straightforward shifting under load issue.
How did you get to a frame stiffness issue, and how exactly did the frame break (if it did).?
Without very detailed and specific descriptions, we're shooting blindly on a dark foggy night.
Last edited by FBinNY; 09-17-22 at 11:55 PM.