Bug: Updating citation collections

I'm getting the following error when trying to remove a collection from a citation:

org.hibernate.exception.ConstraintViolationException: could not execute batch could not execute batch (conn=105321) Duplicate entry '1609-BOLD' for key 'uq_bib_citation_collection'

The record in the database is:

{
  "id": 1609,
  "active": false,
  "version": 8,
  "uuid": "0081b623-6704-4dec-8d8a-c4a4effd3ef8",
  "title": "Cloning and expression of a wild eggplant cytochrome P450 gene, StoCYP77A2, involved in plant resistance to *Verticillium dahliae*",
  "publicationYear": 2015,
  "authors": [
    {
      "lastName": "Yang",
      "otherNames": "Liu"
    },
    {
      "lastName": "Shi",
      "otherNames": "Ce"
    },
    {
      "lastName": "Mu",
      "otherNames": "Xiaoying"
    },
    {
      "lastName": "Liu",
      "otherNames": "Chao"
    },
    {
      "lastName": "Shi",
      "otherNames": "Ke"
    },
    {
      "lastName": "Zhu",
      "otherNames": "Wenjiao"
    },
    {
      "lastName": "Yang",
      "otherNames": "Qing"
    }
  ],
  "keywords": [
    "Turkey berry",
    "Solanum torvum",
    "Neglected crops",
    "NUS"
  ],
  "collections": [
    "GCCS",
    "BOLD",
    "Biotechnology",
    "Plant breeding",
    "Cultivation and agricultural practices",
    "BOLDWP7"
  ],
  "taxonomyFamilies": [
    "Solanaceae"
  ],
  "taxonomySpecies": [
    "Solanum torvum"
  ],
  "instituteCodes": [],
  "doi": "10.1007/s11816-015-0355-6",
  "urls": [
    "http://dx.doi.org/10.1007/s11816-015-0355-6"
  ],
  "publication": "Plant Biotechnology Reports",
  "publisher": "Springer Science and Business Media LLC",
  "language": "en",
  "volume": "9",
  "issue": "4",
  "pages": "167-177",
  "serialNumber": "1863-5474",
  "type": "JOURNAL_ARTICLE",
  "downloadUrl": null,
  "abstractText": "Plant P450 enzymes are key to plant responses to environmental stresses, including pathogen defense and secondary metabolite biosynthesis. In this study, a cDNA sequence, *StoCYP77A2*, was cloned from *Solanum torvum* in response to *Verticillium dahliae* infection. *StoCYP77A2* expression increased in infected plants, particularly in stems, and when introduced into tobacco, enhanced resistance to *V. dahliae*. This suggests *StoCYP77A2* aids in producing antifungal compounds, contributing to plant defense.",
  "sourceType": null,
  "relevance": null,
  "owner": {
    "id": 57,
    "uuid": "c0536c85-bcf4-4734-aadc-b8bd0eab2f31",
    "shortName": "GCDT",
    "name": "Global Crop Diversity Trust",
    "email": null,
    "phone": null,
    "address": null
  },
  "state": "DRAFT",
  "statusText": null,
  "linkedCitation": null,
  "sourceData": "TY  - JOUR\r\nDO  - 10.1007/s11816-015-0355-6\r\nUR  - http://dx.doi.org/10.1007/s11816-015-0355-6\r\nTI  - Cloning and expression of a wild eggplant cytochrome P450 gene, StoCYP77A2, involved in plant resistance to Verticillium dahliae\r\nT2  - Plant Biotechnology Reports\r\nAU  - Yang, Liu\r\nAU  - Shi, Ce\r\nAU  - Mu, Xiaoying\r\nAU  - Liu, Chao\r\nAU  - Shi, Ke\r\nAU  - Zhu, Wenjiao\r\nAU  - Yang, Qing\r\nPY  - 2015\r\nDA  - 2015/06/24\r\nPB  - Springer Science and Business Media LLC\r\nSP  - 167-177\r\nIS  - 4\r\nVL  - 9\r\nSN  - 1863-5466\r\nSN  - 1863-5474\r\nER  - \r\n"
}

I'm trying to remove "GCCS" and when hitting Save, the error above is displayed.