Contrasts depend on order in which data appears in factors

[sens]

It should ideally be sorted by alphabetically or the user should specify what the reference is.

[GregFa]

Thanks for the suggestion. At the moment, our contrast handling for building the design matrix mirrors StatsModels.jl. Since the current implementation is intentionally aligned with StatsModels.jl, we prefer to keep it as-is for now to maintain consistency and user expectations. We can certainly revisit adding an explicit alphabetical default and/or user-specified reference levels in a future update, but for now we'll stick with the StatsModels-compatible behavior.