The Pancake Batter Anomaly - S1-E11
Corrected entry: When Leonard is standing outside the apartment his hair is tucked under the band of the wireless cam he has on his head, but when he is crawling on his hands and knees through the apartment his hair is out from under the band and is hanging in front of his face.
Correction: They also find a gift bag in this time so it's clear there has been a gap of some time. Enough to sort the headband out.
Ssiscool ★