zod validation behaving differently if component is multipleCapable

[Viicos]

The following is the (simplified) cosignv2 component schema:

const buildDefaultValueSchema = (intl: IntlShape) => {
  const emailSchema = z
    .string()
    .email()
    .optional();

  return z.object({defaultValue: emailSchema});
};

const schema: EditSchema = ({intl}) => buildCommonSchema(intl).and(buildDefaultValueSchema(intl));

export default schema;

As it is, it does not allow a defaultValue of null.

This is the (simplified) email component schema, which is multiple capable:

const buildDefaultValueSchema = (intl: IntlShape) => {
  const emailSchema = z
    .string()
    .email()
    .optional();

  // case for when component.multiple=false
  const singleValueSchema = z
    .object({multiple: z.literal(false)})
    .and(z.object({defaultValue: emailSchema}));

  // case for when component.multiple=true
  const multipleValueSchema = z
    .object({multiple: z.literal(true)})
    .and(z.object({defaultValue: emailSchema.array()}));

  return singleValueSchema.or(multipleValueSchema);
};

const schema: EditSchema = ({intl}) => buildCommonSchema(intl).and(buildDefaultValueSchema(intl));

export default schema;

Similarly, defaultValue shouldn't accept null (or [null, ...]), but it does.

I wasn't really able to reproduce (see playground), so I suspect this is an (other) issue with the formik adapter library