Custom field value is both null and not-null (?)

I'm querying an issue by ID and with some fields and custom fields.

When I look for a field by name, I can get the entity (in this case, an instance of `SimpleProjectCustomField`):

As you can see, the field's properties are duplicated.
In the case of `Value`, it's once set as `null` and the other time with the actual correct value.

When reading the value, I always get the `null` one.