Bug on forms based on security roles?

We have faced with our Dynamics CRM Online instance a bug with the security roles. We have defined for our different sales and service teams different views (accounts, contacts, opportunities). 

It happened in the past 2 weeks several times that randomly some users suddenly saw a different view. We haven't changed the security roles for the affected users and also a copy of the security role didn't help. 

What helped was the deletion of the cache and the cookies within the Internet Explorer, but we hesitate to set the browser settings to delete cache and cookies for each session. Many users have cookies they need for their daily work. 

Has anyone experienced the same with Dynamics CRM Online and did you get a sufficient solution?