Docker exit code

Hello all,

I am confused to how the exit code from a process inside a container gets passed to docker.
I have a container which runs an npm run script.
The npm run script fails with exit status 1 but it seems that the exit status is not passed to the docker process itself because Bamboo flags the build task as success.

30-Sep-2019 15:43:53 	npm ERR! Exit status 1
30-Sep-2019 15:43:53 	npm ERR!
30-Sep-2019 15:43:53 	npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
30-Sep-2019 15:43:53 	
30-Sep-2019 15:43:53 	npm ERR! A complete log of this run can be found in:
30-Sep-2019 15:43:53 	npm ERR!     /root/.npm/_logs/2019-09-30T13_43_53_321Z-debug.log
30-Sep-2019 15:43:54 	Stopping containers 
30-Sep-2019 15:43:54 	b3efbe0710cc
30-Sep-2019 15:43:54 	Removing containers
30-Sep-2019 15:43:55 	b3efbe0710cc
30-Sep-2019 15:43:55 	Finished task 'Script' with result: Success

The container is started with the docker runcommand.

Any advice?
Thanks in advance.
Regards