It's not a problem in principle to selectively deactivate those warnings for the TBB headers, but I am a bit baffled by the fact that I cannot reproduce it and by the fact that similar warnings are not being produce by, e.g., Boost or other libraries obake depends on. It makes me think there's something specific in the way TBB is being included in your setup.
It could also be that TBB is being configured/built in a different way and on my system the offending code is bracketed in the dead branch of some
What version of VS2019 is this? There is a couple of CI builds using MSVC 2019 which works: