I think you've answered it, the ground for this one has been wetter than the other. there is no reason for the flowers to fail. if the area is very wet when you lift the lily dig in some grit to help the drainage and if you plant it back in the same place incorporate more grit then.

Thanks Seaburngirl. I have been on holiday for one week and my poor Tree Lily has been subject to extreme heat. It has given up with the idea of flowering but it is still green on the stem so perhaps next year it will do better. I will add the grit tho'.