My first ones bottomed out, 380cc, its most common in overs, but I’ve seen a lot happen in unders too, mine were unders. It can happen if implants too large and has little support, or when the pocket made is too large for the implant, which was what happend in my case, if I laid down they just fell straight to the sides and moved everywere. To look at they were both low on the chest, nipples pointing upwards and not central, specially from the side. My right was worse then left so fell further down also making them slightly wonky. Then the left had double bubble, which now on my 2nd op has started to get worse again. Hope that helps xx