I have some new findings.
I believe it's caused by the Core-script "/usr/bin/select"
However, I'm not sure if it's related to the new beta release.
Team Tiny Core is pleased to announce that Tiny Core 13.0 Beta1 is available for public testing:
Changelog for 13.0 Beta1:
* select: require that "break" used in awk scripts
Anyway, I've attached the patch just in case.