Okay so I’ve done some testing and indeed it seems like the translations are coming from WP Core. I don’t think it’s currently possible to avoid this issue other than naming your fields something that does not exist in core.
I will include @elliot in this conversation to see what his view on this is. I could imagine an additional option for the acf_settings() function where one could set the text-domain to a custom.
Welcome to the Advanced Custom Fields community forum.
Browse through ideas, snippets of code, questions and answers between fellow ACF users