Wow, incredible. I recently interviewed (as hiring manager) for 3 separate positions of varying seniority. Cheating is rampant now. I'd say at least 80% were using ChatGPT to lookup answers. One candidate had a 3rd party operate ChatGPT for her.
Yes, the nice thing about it being a desktop app is that all interview platforms are supported - browsers are unable to detect these desktop apps due to inherent limitations. There's a bunch of competing services so it's likely your candidates were running something.
Do you support Codility?