Adding not encrypted data to a template does not work

[sburkard]

Which component:
controller

Describe the bug
When I use plaintext keys of the sealed secret in a "template", the variable is replaced with "" instead of the real value.
In contrast, it works perfectly when I use encrypted keys as variables (as documented).

Don't know, if this really is a bug or if it was never intended to work. However, it would be nice to have this ability.

To Reproduce
Steps to reproduce the behavior:

1. Create a sealed secret with encrypted and plaintext keys. Here, password is encrypted, username is plaintext. The result is the same if I put the username key in "data" instead of "stringData".

apiVersion: bitnami.com/v1alpha1
kind: SealedSecret
metadata:
  name: mySecret
spec:
  encryptedData:
    password: encrypted password
  template:
    stringData:
      username: "myUsername"
    data:
      settings.xml: |-
		<server>
			<id>maven</id>
			<username>{{ .username }}</username>
			<password>{{ .password }}</password>
		</server>

2. Deploy the secret
3. Check the resulting secret

Expected behavior
I expect the settings.xml key to contain both username and password, but the username variable is not replaced with the plaintext value. Instead it is replaced with ""

<username><no value></username>
<password>plaintext password</password>

Version of Kubernetes:

• Output of kubectl version:

Client Version: v1.30.2
Kustomize Version: v5.0.4-0.20230601165947-6ce0bf390ce3
Server Version: v1.26.15+4818370