imagePullSecrets mysteriously get `registry-` prefix - kubernetes

Question

I am trying to deploy the superset Helm chart with a customized image. There's no option to specify imagePullSecrets for the chart. Using k8s on DigitalOcean. I linked the repository, and tested it using a basic deploy, and it "just works". That is to say, the pods get the correct value for imagePullSecret, and pulling just works.
However, when trying to install the Helm chart, the used imagePullSecret mysteriously gets a registry- prefix (there's already a -registry suffix, so it becomes registry-xxx-registry when it should just be xxx-registry). The values on the default service account are correct.
To illustrate, default service accounts for both namespaces:
$ kubectl get sa default -n test -o yaml
apiVersion: v1
imagePullSecrets:
- name: xxx-registry
kind: ServiceAccount
metadata:
creationTimestamp: "2022-04-14T14:26:41Z"
name: default
namespace: test
resourceVersion: "13125"
uid: xxx-xxx
secrets:
- name: default-token-9ggrm
$ kubectl get sa default -n superset -o yaml
apiVersion: v1
imagePullSecrets:
- name: xxx-registry
kind: ServiceAccount
metadata:
creationTimestamp: "2022-04-14T14:19:47Z"
name: default
namespace: superset
resourceVersion: "12079"
uid: xxx-xxx
secrets:
- name: default-token-wkdhv
LGTM, but after trying to install the helm chart (which fails because of registry auth), I can see that the wrong secret is set on the pods:
$ kubectl get -n superset pods -o json | jq '.items[] | {name: .spec.containers[0].name, sa: .spec.serviceAccount, secret: .spec.imagePullSecrets}'
{
"name": "superset",
"sa": "default",
"secret": [
{
"name": "registry-xxx-registry"
}
]
}
{
"name": "xxx-superset-postgresql",
"sa": "default",
"secret": [
{
"name": "xxx-registry"
}
]
}
{
"name": "redis",
"sa": "xxx-superset-redis",
"secret": null
}
{
"name": "superset",
"sa": "default",
"secret": [
{
"name": "registry-xxx-registry"
}
]
}
{
"name": "superset-init-db",
"sa": "default",
"secret": [
{
"name": "registry-xxx-registry"
}
]
}
In the test namespace the secret name is just correct. Extra interesting is that postgres DOES have the correct secret name, and that uses a Helm dependency. So it seems like there's an issue in the superset Helm chart that is causing this, but there's no imagePullSecrets values being set anywhere in the templates. And as you can see above, they are using the default service account.
I have already tried destroying and recreating the whole cluster, but the problem recurs.
I have tried version 0.5.10 (latest) of the Helm chart and version 0.3.5, both result in the same issue.
https://github.com/apache/superset/tree/dafc841e223c0f01092a2e116888a3304142e1b8/helm/superset
https://github.com/apache/superset/tree/1.3/helm/superset