Why didn’t I get a guaranteed appearance from the featured character in the Prayer of The Fleeting on my 100th Invoke?

The requirement to guarantee that the featured character in the Prayer of The Fleeting appears is as follows.
・If the featured character does not appear after pulling 99 consecutive times, they will appear on the 100th pull

If you do not pull 100 times in the same Prayer of The Fleeting, the requirement above will not be fulfilled, and there will be no guaranteed appearance from the featured character.

To see your current pull count, please locate the “Details” button on the lower-left corner of the Prayer of The Fleeting screen. Tapping it will open the Invocation Details screen, and from there you can check your current pull count, written as:
・Your pull count for the guaranteed appearance is currently【X/100】
*When the featured character appears in the Prayer of The Fleeting, your pull count will reset to 0.