Reproducer :

------
apiVersion: v1
kind: ConfigMap
metadata:
  name: test
data:
  Dockerfile: |
    FROM registry.access.redhat.com/ubi9/ubi
    ARG FOO
    RUN echo $FOO
------

# This works
------
apiVersion: tekton.dev/v1
kind: TaskRun
metadata:
  name: test-ct
spec:
  params:
    - name: IMAGE
       value: 'image-registry.openshift-image-registry.svc:5000/test/test:latest'
    - name: BUILD_EXTRA_ARGS
       value: '--build-arg FOO="abc def"'
  serviceAccountName: pipeline
  taskRef:
    kind: ClusterTask
    name: buildah
  workspaces:
    - name: source
       configMap:
         name: test
------         


# Error: accepts at most 1 arg(s), received 5
------
apiVersion: tekton.dev/v1
kind: TaskRun
metadata:
  name: test-t
spec:
  params:
    - name: IMAGE
       value: 'image-registry.openshift-image-registry.svc:5000/test/test:latest'
    - name: BUILD_EXTRA_ARGS
       value: '--build-arg FOO="abc def"'
  serviceAccountName: pipeline
  taskRef:
    resolver: cluster
    params:
    - name: kind
       value: task
    - name: name
       value: buildah
    - name: namespace
       value: openshift-pipelines
  workspaces:
    - name: source
       configMap:
         name: test
------

# This is also fails :

------
apiVersion: tekton.dev/v1
kind: TaskRun
metadata:
  name: test-t
spec:
  params:
    - name: IMAGE
       value: 'image-registry.openshift-image-registry.svc:5000/test/test:latest'
    - name: BUILD_ARGS
       value:
         - FOO="abc def"
  serviceAccountName: pipeline
  taskRef:
    resolver: cluster
    params:
    - name: kind
       value: task
    - name: name
       value: buildah
    - name: namespace
       value: openshift-pipelines
  workspaces:
    - name: source
       configMap:
         name: test
------