I joined as I had the same issue. I completed a cleaning cycle, had a deep clean completed notification and it was still showing as incomplete. 

I turned the machine off at the wall and back on after a few minutes. After a reboot it works fine.

No guarantee if this is the correct approach. It certainly worked for me. 

Hi @Svetlana We hope the recommended steps above have resolved the issue that you’ve been having with your Dyson. If the issue is unresolved and you need further assistance, please get in touch via our local WhatsApp channel, where one of our team will be happy to discuss the next steps. To do this, simply click on our Guides and manuals link, navigate to the ‘Contact us’ section of the page and start a WhatsApp conversation.