"Water wobbles" are a commonly discussed phenomenon for some baby swim schools. Parents are told that babies will reach a stage in their progress over a course of lessons when they suddenly stop enjoying swimming quite as much as they did at first - some even refuse to get into the pool. Parents are reassured that this is normal, it happens to all babies, and that the solution is to ease back and reduce the number of submersions you are doing to the baby until the fear of water passes.
Babies aren't born scared of water, but they will become scared of the water if they are working at a pace that isn't right for them. In a class which is correctly paced, with plenty of time for a parent to work with their baby, there is no reason for a child to develop a fear of the water - the water wobbles simply don't exist. In a class where things are being done to rather than with the baby (including adult-led submersions), the baby will understandably get to an age where they will start to resist.
That isn't to say a child will never be upset in an effectively taught lesson - they could be teething, hungry, tired or just not in the mood to swim. But a suddenly developed fear of the water should ring alarm bells.
Rather than blaming our babies, we need to look at ourselves - are we really paying attention to our children? Are we fostering and inspiring a love of water, or are we pushing a baby through a checklist?
I've never encountered the water wobbles, and I hope I don't have to. If we let the child take the lead, there's no reason why a suddenly developed fear of water should be a part of our lessons.