I brought a red Abyssinian Banana in for the winter and it was doing well up until recently. In the past two weeks leaves have buckling under there own weight, its not just the old ones too, today one of the new leaves did it. I have noticed that the stems of the leaves are soft. there is no visible discoloration on the leaves, what could be causing this? There were a few spider mites on it a while back but could they do all this?