has anyone else observed this?
I usually build my own package for "Windows", so maybe it is just my builds script, but that seems par for the course under "MinGW".

I can't speak to anything about "Ubuntu".

My understanding, and only that, is that a lot of work needs to be done for "libstdc++" before the implementation has the proper safety the respect to the standard. You may not, and probably will not, be able to match your own expectations with "libstdc++" for a bit longer.

Soma