NPM: npm update is not changing the version in package.json

I have an express project. One of the dependencies is updating in package-lock.json and installing the new version, but the one in package.json is not changing.

package.json

"x-dependency": "^1.73.0",

package-lock.json

"x-dependency": {
  "version": "1.73.1",
  "resolved": "",
  "integrity": "",
  "requires": {
    "lodash": "^4.17.11"
  }
},

Notes:

This is a custom dependency that I manage in my registry.

NPM version is 6.14.8

Both files have the same permissions.