It seems that sub builds of Mac mac_host_engine have a time limit of 1 hour, however, the builds tend to take ~45 minutes. When it runs on a newly upgrade Mac-14 host, it may timeout if Xcode is also being re-installed, which will push the time it takes over an hour.

https://ci.chromium.org/ui/p/flutter/builders/prod/Mac%20mac_host_engine/10985/infra