Cannot create install media for macOS Sierra

Trying to create USB for an older MAC that can only run up to 10.12. No matter what I try is will not prompt to erase the USB device (I've tried multiple). It just sits there for a while and then gives the following error.

My macbook is running Big Sur 11.4

The version of Sierra I downloaded from Apple has a create date of 14 July 2017

Following output from terminal. The temps of all cores spike to around 92 Celsius while this is processing.

sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ macOS\ Sierra.app

2021-07-02 09:49:28.372 createinstallmedia[14268:283612] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Couldn't posix_spawn: error 35'

*** First throw call stack:

(

0   CoreFoundation                      0x00007fff2058e87b __exceptionPreprocess + 242

1   libobjc.A.dylib                     0x00007fff202c6d92 objc_exception_throw + 48

2   Foundation                          0x00007fff21321a91 -[NSConcreteTask launchWithDictionary:error:] + 4990

3   Foundation                          0x00007fff21347c69 +[NSTask launchedTaskWithLaunchPath:arguments:] + 146

4   createinstallmedia                  0x000000010ac73968 createinstallmedia + 6504

5   libdyld.dylib                       0x00007fff20436f5d start + 1

)

libc++abi: terminating with uncaught exception of type NSException