Why would a sealed burrata turn blue?

I bought a burrata that was still completely factory sealed. I stored the sealed container in the fridge, but I wrapped the container in a magazine while it was in there.

When I opened it later, the outer mozzarella skin had a faint blue tint. The burrata had never been opened before, and the seal looked intact. The inside filling still looks white.

I’ve bought burrata many times before and never seen this happen. I also found photos online of ‘blue mozzarella’ that look similar.