I've tried to isolate the issue by constructing a simple version of the problem but I wasn't able to reproduce it. It's probably an edge case or something specific to my setup.

if its a browser build you get generate a build report. that lists everything that was used and why https://shadow-cljs.github.io/docs/UsersGuide.html#build-report

I was able to resolve my issue by using clojure -M:shadow-cljs compile ... rather than npx shadow-cljs compile ...

I'll try to put together a repro of the issue. Thanks for your help!

I know a bit more now: this seems to have been caused by an old version of shadow-cljs being specified in deps.edn. A newer version was used in package.json but it seems shadow-cljs will prefer using the clojure-cli one?

it is not about preferring. when using deps.edn that is the only version that matters. package.json only controls the version if using shadow-cljs.edn only

:thumbsup: that aspect of it surprised me, I'm sure people using deps.edn usually know what they're doing. Thanks for answering my questions!