Just bought this and noticed the rot, should I return it?

I bought this triple San Pedro cactus for my wife’s birthday. It is about 8 feet tall including the 2 foot pot. One of the three branches (is that the right term?) has this rot at the bottom.

The cactus was pretty expensive so I don’t want it to die on us. The “branch” with the rot is the tallest one.

Thanks in advance!