I did it exactly that way. For some reason they were horrible, the freezer bags seemed to impart a horrible taste. Tossed out a lot of zuke and yellow squash slices.
Oh no! Sounds bad. I use vacuum seal bags, have had no trouble, and you can heat the contents.
Long ago I took zucchini, cut into chunks of just the flesh, dumped the seeds. Salted the chunks heavily and let drain for a day. Used a foodsaver vacuum sealer and then froze. They turned out ok not too watery and used them in soup or stew. Did the same think one year when I had a lot of butternut squash, just did not salt them. Vacuum sealed and froze. They were great for making butternut squash soup. No bad taste, no frost either.