I have seen several on the canna sites that do that. Maybe it is just that cannas characteristic.
Sky~~

Thanks Sky, I've wondered if it's this certain type too. Not a very good trait. But, it seems that in the week or so since I posted this, I have had a few blooms that stayed up right. These seem to be the first to sprout in spring and then seem to bud very quickly, almost as though the plant is growing too fast and blooms before it can handle the weight of it's on bloom. I've noticed these last few are shorter stalks (for lack of a better word) and the blooms are staying up. The mystery continues... Thanks and peace..