Center Collapse From Too Much Butter?

Hi All,

From Beth Hensperger's Bread Machine Cookbook, I recently made my version of a 9-grain honey 2-lb bread in my Zoji machine.  The first loaf turned out fine but the following week's second loaf had serious center collapse.

The only difference between the two bakes was that with the second loaf I added 1T poppy seed and 1T chia seed.  Also, the recipe calls for 4T butter and I may have overdone it a bit.  Would too much butter cause the center to cave in?

Thanks,

 Dan