First 2.5 shots of entire negative completely black (overexposed)

Developed my first roll of film (TMAX100 in D-76 & TF-4) tonight and at first glance the images are about 1-2 stops underexposed I think. However, there are 2.5 shots completely missing. This was shot in a studio with a strobe, does anyone know what could be causing this?

Possibly the roll wasn't rolled up tight enough after removing from the camera, there's also edge fogging past the lost frames which would be indicative of this. Also once taken out of the camera don't leave out in the light or near flash equipment you're using.

Ian

Yes I think you're right. I remember accidentally opening the film back then having trouble fiddling with the paper and it having it loosen up before I realized what I was doing. There are also light burns along the rebate edge of the good photos.

Edit: after drying my film, I see there is some detail left in the completely overexposed parts so I'm glad this wasn't a camera issue.