So I went in an read the actual ruling document https://www.courthousenews.com/wp-content/uploads/2019/01/Bi... (only 8 pages) and it pretty much made sense for me (IANAL ofc).

McD’s lawyers screwed up, not submitting required evidence of actual use in years 2011-2016. They printed out webpages with promo materials and a wikipedia page (as article correctly points, “duh, we are McDonalds”) - not a great proof of anything for any court. Then submitted some packaging of the product.

Not any evidence that the product was actually sold and trademark used in those five years - no sales figures, website traffic stats… As said, makes sense to me

Edit: that said, still makes no sense why were they challenging the use of Big Mac in the first place… shrugs