I did end up messaging Winspace yesterday. They replied saying, "According to our engineer, it is normal, does not affect safety performance."
If that's their thought on it, I'm not going to be able to convince them to replace it or anything

I feel extra weird about it because I'm building it for a friend, not for myself... on the upside, she's small and has never done more than 700w so at least she's not a ripping 1700w sprints or anything. The situation does leave me feeling a little concerned but I don't feel like I have much choice other than to take Winspace at their word.
I am planning to use one of the thread-together Wheels Manufacturing BBs so hopefully that reinforces the area more than using a cheap, two-piece shimano bb.