probably but my dd has size 4 avent teats (so cant get bigger) and it makes the squeaky noise. it means they arent letting enough air back into the bottle, so it is pulling the air in through very small gaps between the teat and neck of the bottle. if you worry about it take the teat out of her mouth every now and again and let the air be replaced in the bottle.
its not a real problem, i doesnt harm her or the bottles!