Rerender the feedstock after adding python_min. conda-smithy needs to re-read the meta.yaml and adjust your .ci_support files to include the relevant variables obtained from the global pinnings Klaus is referring to.
@jaimergp : Thanks! that must be it – it was rerendered recently, but not after I added the variable – I always get confused about when / how to rerender. I thought it would be there whether it was used or not.
And I’m now seeing the bot is doing this for me on other recipes …