Considering that the developer is saying "not for production" but the users are saying it works great in production, I'd say the comparison should be "unknown competence > unknown incompetence"
Ah, yes, love those, cobbled together embedded compilers. Not a word in the Release.Me about the quirks. Just a "STABLE!!!".
Like binary C-Operators will only work on the first 8 bits, the rest is up there and needs to be shifted in and out.. basically work it out yourselve, once it wont work.
Then explain to the manager, that his hot project tooling from the megacorp upstream was basically license-brokken copy pasted garbage from some hobbyist half way around the world). And get a no, when asking for at least posting the patches back.
Or the "Working feature" which is just some api header, going into a inlined binary blob returning some constant. Which is just some flytrap to get you to drive by develop it for them. Twelve angry part time devs, make up one full working project.
The only professional in some industries is looking at you every morning from the mirror, begging for a mercy killing.
Garbage-quality projects don't bother putting such warnings. They might even not be aware they are garbage.
(/s)