LKW,
On a triple crank set, the middle chainring have small indents on the inside face for the chainring bolt/nut flange. Those indents are on the outer surface of the outer/big ring. When you move the big ring to the middle position, you lose those indents as they now face the spider. The flanges of the fixing bolts for that ring will thus protrude out more toward the small ring. With certain gear combination (small chain ring and small cog) the chain will rub against these flanges.
I solved that problem by adding 1mm washers between the inner granny chain ring and the spider moving it more medial and away from the big chainring.
The 48/30 crankset with a 11-32 cassette shift flawlessly for me. I cannot imagine that a 50/32 would cause any problem. The 11-36 cassette, on the other hand, may require some modification to the DI2 rear deraillleur.
If you already have a 30t granny it may be easier to switch out your cassette than to buy a 32t granny and still have to modify your rear derailleur.
Have fun experimenting.
CJ