Generated yaml from jsonnet does work, but the .drone.jsonnot doesn't


I’m facing a strange issue here, I have written a .drone.jsonnet that is valid and can generate a working yaml version (using drone jsonnet --stdout), that I copied manually and pasted as .drone.yml and Drone CI does build it with no problem, but when I use the original .drone.jsonnet file as the main configuration file, the build outputs an error.


Command I use for generating the yaml
docker run --rm -it drone/cli jsonnet --stdout

The build error from tagging docker image using ${DRONE_BRANCH/\//-}