Freezer burn?


Has anybody had their milk get freezer burnt? I got some milk out from July that was stored in parents choice and nuk bags and when I thawed it, it smelled funky. My toddler refused it (this was before I knew that it lost the antibodies and was pointless to give him) but my 4 month old drank it with no problem. I wasn't sure if it was bad, freezer burnt or if I just had high lipase levels. I took some out from a week ago stored in lansinoh bags and it had no smell at all so I feel like I can rule out the lipase issue. So now I'm wondering if it is just too old or if the bags aren't good. It's been stored in a deep freeze. Anybody have some insight? I'm wondering how I know what milk to toss.