I had a similar problem a few days ago. For me it was the cookie consent warning, which appeared after cache clearing.
Try comparing images (expected and at time of failure): double click on failed test step, and compare them.
Also try extending delays just for resloving an error.
answered on 18 Jul 2014, 11:31 AM
Have you upgraded to Chrome 36?
This is a know issue with the latest Chrome. Our development team is working on the fix.