npm audit fix removes integrity value for ssri package

Question

I just ran npm audit fix and after that checked the changes in package-lock.json.

before npm audit fix:

    "ssri": {
      "version": "6.0.1",
      "resolved": "https://registry.npmjs.org/ssri/-/ssri-6.0.1.tgz",
      "integrity": "sha512-3Wge10hNcT1Kur4PDFwEieXSCMCJs/7WvSACcrMYrNp+b8kDL1/0wJch5Ni2WrtwEa2IO8OsVfeKIciKCDx/QA==",
      "requires": {
        "figgy-pudding": "^3.5.1"
      }
    },

after npm audit fix:

    "ssri": {
      "version": "6.0.1",
      "resolved": "",
      "requires": {
        "figgy-pudding": "^3.5.1"
      }
    },

How does that make sense? Doesn't this even decrease security?