Property 'includes' does not exist on type 'string[]'

Project Unionversity

Link to course:
TypeScript: Project Unionversity

In this project, the code editor highlights the method .includes in the line
return event.keywords.includes(options.query)

When hovered over it, it reads:

Property 'includes' does not exist on type 'string[]'.(2339)

The typescript compiler does not throw an error and the code runs as expected.
I logged event.keywords: it is an array of strings. So I assume that the line is correct and should not be highlighted. So maybe the typescript config file should be updated?

btw: I missed a tag typescript.