I was looking at Azure AD Sign in reports. It looks like the reports are only showing signs in from a Windows device. I thought it showed attempted signs in mobile devices too? Is that correct? Or has something gone wrong with the reports?
E.g I checked my own logins. There's no events from the 20th to 24th May because I was on leave. However I had checked some emails in between those dates via mobile. There's no log of this.
Checking email and in general performing actions within applications doesn't necessarily mean you've gone through the full login experience. In most cases, the application will simply use a refresh token, which can be valid for 90 days or even more. Until it expires, you will see no login events for the given application/device combo.