From https://specification.modelica.org/master/synchronous-language-elements.html#modelica:clock-rational:

At the start of the simulation, \lstinline!previous($\mathit{intervalCounter}$)! = \lstinline!$\mathit{intervalCounter}$.start! and the clocks ticks the first time.

What is the point of saying that previous(intervalCounter) = intervalCounter.start; isn't that just the definition of previous, and totally irrelevant for the rational interval clock since the $interval_{i}$ is defined based on intervalCounter, not previous(intervalCounter)?

I suppose some relevant background can be found in #2022.