A “Fixed” distribution is not a distribution! - it is a fixed value.
A sample from this distribution will always return the value in the “Fixed Value” field.
This facility enables randomness to be removed from an element of the simulation but also enables “Named” distributions to be used to return fixed values. As a fixed value is not a distribution, it is commonly used for various purposes. These can be timings which are (assumed to be) fixed or also setting labels.