It allows me to go well to download the apk of fdroid. Whenever you use the search engine. in Spanish look: https://f-droid.org/repo/org.fdroid.fdroid_1011050.apk but if you use the blue button on the main page. The error that you comment comes out.
Sorry for posting another answer, but it was not allowed to modify my previous one.
I imagine the problem must be that. Because I was looking at the fdroid application in other languages. And the 1.12.1 is not out yet and in the English one it is. In other languages the beta is still available. And they will be uploading the new version. But I can not assure you that this is the problem.