buildctl failes to import cache manifest

[rrajpuro]

Running a toolchain with BUILD stage that uses commons/scripts/build_image_buildkit.sh failes to import cache manifest from us.icr.io.
In my opinion, the ERROR is that it is unable to find an image with the tag :latest as the images are stored with a custom tag as below

# Minting image tag using format: BUILD_NUMBER-BRANCH-COMMIT_ID-TIMESTAMP
# e.g. 3-master-50da6912-20181123114435

Lines 42 and 43 in the script

I believe so because of the following snippet

user@cloudshell:~$ ibmcloud cr image-inspect us.icr.io/<container-registry>/<image>
Inspecting image 'us.icr.io/<container-registry>/<image>:latest'...

FAILED
The image was not found.
Correct the image name or digest reference, and try again.

Can one of the possible solutions be to add an additional tag :latest once the image is built?
so that subsequent toolchains can use cache manifest instead of building the image again from scratch.

P.S. I'm new to Container technology, please correct me if I'm missing something