Has there been a change or an issue with Roles lately?

This morning I was told from our production staff that they no longer have permission to view the app I created for them. When they open the app, they are asked to request permission. The production staff is set to "participant" role. Everything worked find for 2 years until this morning. No setting have been changed, the settings currently look like they should have access. Has there been an update or is there a known issue with the Roles settings? Currently the only way I can get them to have access to the app is to give them administrative privileges - not ideal since there is confidential information about all employees within the app.