I have a food vacuum sealer and the steaks get freezer burned just the same as in a ziploc bag.
Your freezer isn't cold enough &/or there's too much moisture in the bag.
Mine's the foodsaver brand as well, and I don't buy bone-in steaks. The "roll" might be the problem... I cut it to length, seal off the one end, put the meat in, clean around the edge and then seal off the other end. It always seems to me like it seals off the bag too soon, before all the air bubbles are out of the blood it sucks out of the steak and toward the seal. The only moisture in the bag is whatever moisture is in the meat.
Vacuum sealing really sucks.
Can't believe nobody jumped on that one. Speaking of, where the hell is prof?
This is kinda wasteful, but don't trim the bag to length until after its sealed. That extra 2 inches you 'waste' aren't really wasted. If you want to be sure, you just fold that over and seal it again in a 'higher' spot. I found that out pretty quick. It was a good sized fish, too...
I can try two seals per side, but I think the problem is that it hasn't sucked all the air out yet before it seals it off.
Is the bag tight around the meat? If its not, then its not getting all the air out, and you need to adjust the time spent on the vacuuming portion of the sequence. My guess is that you're stopping it before its done. Don't worry about any liquids getting into the vacuum chamber.