What are the dark brown streaks on the surface of the cheese that suddenly appeared within one day?

Knife or hands weren't clean, or something else in the fridge cross-contaminated it.

A simple ruleset I always follow for cheeses, as I often have many types at once in a small fridge.

• Never unwrap it fully [until the very last piece.]

• Use a clean knife for every cheese.

• Never touch the cheese with your hands, use the wrapper it came in, or give it a new one.

• After use, wrap each cheese back in its original wrapper as best you can without touching the inside. Put it in another bag, twist & seal.

• Don't store different cheeses in the same container.

• Be doubly careful if one is a blue cheese - unless you want all your cheese to be blue.

Cross-contamination is the easiest form of food contamination, so don't do it.
Crumbs in the butter/marmite/honey/jam is the easiest way to ruin it long before its time. Cheeses are by definition bacteria-ridden. Keep cheese even cleaner than the jam pot. Keep different cheeses separate.

Looks like something is brewing on your cheese. Dairy products accepts odours and lingering flavours in your fridge with open arms.

If you have a lot of cheese you could consider investing in a cheese cave. Which is just a repurposed wine fridge with the racks removed