Knowledge Base search doesn't work

The Search bar in the Knowledge Base simply doesn’t work.

Opening the debugger, I get the following error:

Uncaught TypeError: Cannot read properties of undefined (reading 'apply') at index.ts:646
    at $._join (index.ts:646:21)
    at $.join (index.ts:362:17)
    at p (index.js:156:1)
    at index.js:707:1
    at e.flaggedInstrument (index.js:126:1)
    at index.js:706:1
    at e.input (index.js:665:1)
    at e.trigger (core_view.js:63:1)
    at e.r [as trigger] (index.js:383:1)
    at e.trigger (ember-events.js:142:30)
    at e.r [as trigger] (index.js:383:1)
    at HTMLInputElement.o (ember-events.js:207:39)