Thank you @Ulanbek!
It seems that the sorting would be for the first value in the series. It’s how the sorting is done but it’s not visible in the first screenshot you posted because it’s grouped by year. If you change it to monthly and sort high to low it will order based on the first option in the series (Dose 0) but will not sort the series. See the screenshot below:
The sorting when there is an option set will always sort based on the first value of the option set but will not sort the option set. This becomes more clear when the period is changed to monthly, but also if we have several years, the sorting will be based on the first option in the option set.
This explains why this was sorted from high to low.
@Ulanbek, initially this is not a bug; however, we can change it to a feature request? But it seems that this gets complicated and needs more discussion. For example, in the screenshot below:
Would it actually be considered correct if it were sorted as the following chart?
Thanks!