When Ray, Robert and Frank eat in the kitchen and Robert says, "Three women, what am I going to do?" he puts his hands up on his temples. In the next shot, they are near his chin.
Robert takes the phone from Marie and sets it on an end table. After cutting to a closer shot of the two of them, then a longer one, the phone is not in the same place.
In season 5 'Meant to Be' where Robert tells Amy he has been speaking with Joanne about getting back together, she is wearing a pink cardigan with flowers on it to dinner. However, in Sister in Law, season 9, she shows the exact same cardigan to Robert as something new she had bought that day. This is only a goof on the part of Sister In Law, as it takes place later and was inconsistent with established details.