This started the same time as the big UI update this week. Both the Box Embed widget and the widget in the Salesforce integration require this security check every time the page is reloaded. It used to only happen once in a while when you first logged in. I have "seamless login" checked in the settings, nothing changed there. This happens with both Okta SSO and username/password accounts.
https://docs.box.com/docs/box-embed
https://appexchange.salesforce.com/listingDetail?listingId=a0N30000001qNeKEAU

