Sometimes bot scripts parse recipes incorrectly, leaving out variables defined in conda_build_config.yaml, leading to failed parsing with UndefinedError, etc. e.g. conda-forge/fenics-feedstock#286
I think it should never be valid in the bot code to parse a recipe without loading conda_build_config.yaml as well, since it leads to hard to debug errors that only ever occur in the bot, never real builds or renders.