For some datasets' dataverse_json exports, there is no `citationDate` key showing what the dataset's citation date is

What steps does it take to reproduce the issue?

• When does this issue occur?
  When looking at the dataverse_json exports of some datasets

• Which page(s) does it occurs on?
  In the dataverse_json exports of some datasets, but not all datasets

• What happens?
  In the dataverse_json exports of some datasets, there is no citationDate key showing what the dataset's citation date is. For example, see the dataverse_json export of the dataset at https://doi.org/10.7910/DVN/PZBQTD:

  

  In the datasetVersion key, there should be a citationDate key, but there isn't. For datasets where there is a citationDate key, I've seen it right below the publicationDate key, like the part in orange in the screenshot below.

• To whom does it occur (all users, curators, superusers)?
  All users, curators, superusers

• What did you expect to happen?
  In the dataverse_json export of the dataset, the datasetVersion key should include a citationDate key, like there is in the dataverse_json export of the dataset at https://doi.org/10.7910/DVN/5KLDV6:

  

Which version of Dataverse are you using?
v6.9 (on Harvard Dataverse)

Any related open or closed issues to this bug report?

• https://github.com/IQSS/dataverse/issues/9656
• https://github.com/IQSS/dataverse/issues/12316

Start by comparing the two linked dataverse_json export responses for the affected dataset and the dataset that includes citationDate, then review related issues 9656 and 12316. Done means the datasetVersion object in exports includes a citationDate key for datasets currently missing it, without removing it from datasets where it already appears.