The Mothers - S3-E17
Plot hole: When the "refrigerator" falls on Tobias's mom, the boys are watching from a side view. It is later revealed that the fridge was just a cardboard cutout. The boys were watching from the side, so how did they not notice it?
Plot hole: We learn the rangers were pre-selected to join the team and were in waiting until called to duty, but the yellow rangers sister just passed the legacy onto Emily, who was only a child.