So I called a lactation helpline and they told me its ok for my thawed milk to taste sweet yet a little bitter at the same time. Has anyone else experienced this?

I posted a few days ago about my freezer getting messed up and I found about half of my stash (A LOT of milk) in a slushy state (not completely defrosted at all) and I decided to refreeze and just do the taste test when I thawed to see if it went bad or not. So when I thaw it, it mixes well and does not smell bad at all, buuuuuut, it does taste a little bitter.

I have thawed out BM that was not from this "bad batch" and it tastes sweet and bitter, but not as bitter.

Does this mean my "slushy bad batch" is bad? I just cant come to terms with throwing away about 500 or more oz of BM. So much hard work.

Is there anything else I can do with it?