Yeah it's pretty wild. Even more dangerous is the plant ID app that mentions it's sometimes used as a substitute for sage, without mentioning the toxicity at all. It gives this one-paragraph blurb:
Common tansy (Tanacetum vulgare) is a plant native to Europe and Asia. The common tansy has been introduced in other global regions and is sometimes considered to be an invasive species. The common tansy can be used as a substitute for sage.