Cypress 12.14 TypeError: Cannot read properties of undefined (reading 'set')

I've encountered a very strange problem with Cypress where its unable to 'get' any element. All my commands work until the code gets to cy.get.

My code:

cy.get('#username').type('blueUser');

Error:

Cannot read properties of undefined (reading 'set').

This is really puzzling because I know the element exists because I used older versions of Cypress and it worked just fine. I even tried the Cypress Studio (Record and Playback) and it created identical code to my own but still threw that same error. Help please !

Stack trace pasted into comments:

at get (xxxxxxxxxx.com/__cypress/runner/cypress_runner.js:148433:10)
at $Command.overridden (xxxxxxxxxxxxxx/__cypress/runner/cypress_runner.js:159898:21)
at cyFn (xxxxxxxxxxx/__cypress/runner/cypress_runner.js:160714:19)
at <unknown> (xxxxxxxxxxx/__cypress/runner/cypress_runner.js:159444:15)

From previous event:
at CommandQueue.runCommand (xxxxxxxxxxxx/__cypress/runner/cypress_runner.js:159410:8)
at next (xxxxxxxxxxxxxxxx/__cypress/runner/cypress_runner.js:159610:19)
at next (xxxxxxxxxxxxxxxx/__cypr

Thanks for adding the stack trace. As mentioned in comments, the stack is indicating a Cypress.Commands.overwriteQuery() is being used which has used the wrong form of callback.

The docs Custom Queries show

Cypress.Commands.overwriteQuery('get', function (originalFn, ...args) {
  return originalFn.apply(this, args)
})

but if instead you use

Cypress.Commands.overwriteQuery('get', (originalFn, ...args) => {  // arrow function
  return originalFn.apply(this, args)
})

you get errors caused by this being undefined.

The warning is given in the docs:

> The query API relies on this to set timeouts, which means that callbackFn should always use function () {} and not be an arrow function (() => {}).