Go was never truly portable on Linux unfortunately due to its dependency on libc for DNS and user name resolution (because of PAM and other C-only API). Sure, pure Go implementation exists, but it doesn't cover all cases, so, in order to build a "good" binary for Linux you still needed to build the binary on (oldest supported) Linux distro.

If your production doesn't have any weird PAM or DNS then you can indeed just cross-compile everything and it works