Clutch fluid resivoir cap has a hole?

[tips000]

Long story short, I am taking a brakes class in college and learned tonight that brake fluid is hydroscopic, it attracts and absorbs moisture, once it has absorbed so much moisture it's contaminated. My clutch/ brake fluid resivoir cap has a hole in the top! I know there is supposed to be a hole in the plastic with the rubber thing under it to allow the rubber boot to move with the expansion/contraction of the fluid. Mine actually has a hole in the rubber too allowing air into the fluid? My teacher said that he thinks it needs to be replaced but it almost looks like the hole is supposed to be there, it's very clean cut and perfectly centered. It doesn't look like it was accidentally stabbed with a screwdriver or anything.

Is there supposed to be a hole in it?