I assume you have a single Casablanca out of many that is doing this. or many that are. It doesn't matter. I have many Liliums, too many (my name). Out of the many Stargazers I have there are 2 that bloom late. They were blooming as of Sept 26 but have since been taken by frost 2 nights ago. Those 2 bloom in september every year. Why I don't know. I figure its something with the exact soil mixture in that 1 foot of space. Or a combination of conditions. I suppose if I sent out a sample of the soil compared to the rest of the garden I'd get a difference but its not important. Those 2 have done this for 6 years. A nice treat at end of the season. Other than that I can't tell you.