BBB chainring will not fit
When Campagnolo introduced their 11 speed high end groupsets they re-engineered the chainset and introduced 'Micro Precision Shifting' and that new bottom bracket design amongst other features. Whilst they were at it they put the new (and thinner) chainrings on the 9/10 speed groupsets, including yours. Not that yours is compatible with 11 speed - you would have to replace the chainrings for that.

And yes, they have created a bewildering array of parts that are a compatibility minefield, making one suspect Shimano are not so bad after all...

Your BBB chainring is for the earlier 9/10 speed systems and sadly won't fit. Your best option is to put the 53T back on there until you can devote the man-months needed to research, afford and buy a genuine 50T Campagnolo MPS chainring.