At the diner, when Miss Patty is talking to Lorelai, she goes from wearing earrings to not wearing them and back to wearing them again.
The "Dean box" items keep moving around. For example, in some shots the dress sticks out and in others it is tucked into the box.
Lorelai opens the kitchen door to go outside with Babette and the door knob changes sides.
When Lorelai and Rory are discussing Rory's rearranging of the furniture in the kitchen at the beginning there is a large bowl of fruit on the table that disappears during their discussion.
Going by the show time line, this episode should take place in the beginning of January. Dean says he is basing their three month anniversary from Rory's birthday which is in the beginning of October, and three months from then would be January. Yet when Rory wakes Lorelai up at 6 am, it is too sunny outside for 6 am in Connecticut in January.