@Tim_P_Morris is it 1, 2, or both?!
@Tim_P_Morris thinking a little more about it, the (non-)collapsibility difference probably has to do with the relationship between PH and AFT for the Weibull:
\beta_{PH} = -\gamma \beta_{AFT}
@PausalZ Interesting. Another for my 'I'll never fully understand collapsibility' list.
https://www.jstor.org/stable/26511790#metadata_info_tab_contents
@PausalZ Yes I think that's a helpful point
@Tim_P_Morris also just randomly came across this paper
https://pubmed.ncbi.nlm.nih.gov/36271175/