Unhandled rejection error: invalid config key requested when attempting to update Cypress via NPM

I am trying to update Cypress to the latest version using the following provided command:

npm install --save-dev cypress@3.2.0

In previous versions this has worked fine with no errors. Now, when I run this, I keep getting the following error:

Unhandled rejection Error: invalid config key requested: agentn 099cbf610e4ce787    at BadKeyError (/usr/local/lib/node_modules/npm/node_modules/figgy-pudding/index.js:93:23)    at pudGet (/usr/local/lib/node_modules/npm/node_modules/figgy-pudding/index.js:101:5)    at FiggyPudding.get (/usr/local/lib/node_modules/npm/node_modules/figgy-pudding/index.js:27:12)    at Object.get (/usr/local/lib/node_modules/npm/node_modules/figgy-pudding/index.js:159:16)    at new PacoteOptions (/usr/local/lib/node_modules/npm/node_modules/pacote/lib/util/opt-check.js:9:21)    at optCheck (/usr/local/lib/node_modules/npm/node_modules/pacote/lib/util/opt-check.js:63:10)    at Object.manifest (/usr/local/lib/node_modules/npm/node_modules/pacote/manifest.js:11:10)    at fetchPackageMetadata (/usr/local/lib/node_modules/npm/lib/fetch-package-metadata.js:58:10)    at limited (/usr/local/lib/node_modules/npm/node_modules/call-limit/call-limit.js:29:10)    at /usr/local/lib/node_modules/npm/lib/install/deps.js:235:14    at /usr/local/lib/node_modules/npm/node_modules/slide/lib/async-map.js:52:35    at Array.forEach (<anonymous>)    at /usr/local/lib/node_modules/npm/node_modules/slide/lib/async-map.js:52:11    at Array.forEach (<anonymous>)    at asyncMap (/usr/local/lib/node_modules/npm/node_modules/slide/lib/async-map.js:51:8)    at exports.getAllMetadata (/usr/local/lib/node_modules/npm/lib/install/deps.js:206:3)npm ERR! cb() never called!npm ERR! This is an error with npm itself. Please report this error at:npm ERR!     <https://npm.community>npm ERR! A complete log of this run can be found in:npm ERR!     /Users/jaswindersingh/.npm/_logs/2019-03-15T13_32_13_190Z-debug.log

Could anyone point me to what this means and how I can fix it? Never seen this kind of error before?

And as far as I know I've not made any changes to any of my packages in either package.json or package-lock.json etc (from what I have read so far from similar posts)