Many of the STL containers in MSVC are incredibly cursed. Even std::vector is implemented in such a weird way, that you can't debug it easily with any debugger other than Visual Studio. And it's incredibly slow on Debug mode, up to the point that it's unusable... (Because of these reasons I just switched to using my own Vector<T> class recently)

I think there's a very good reason why old gamedevs who were stuck with developing on Windows largely ignored the STL and made their own containers / utility functions: MSVC's STL was just awful.