Rclone combine + 1fichier

Hi, i'm not following the "rule" as nothing new for the bug, just i've found a trick for the problem in a closed topic: https://forum.rclone.org/t/combine-and-1fichier-doesnt-list-files/50640

So if one use combine backend with 1fichier backend, for every file on 1fichier backend this error shown: "Entry doesn't belong in directory".

It's still like that today, but i've found out this: i have a crypt backend, with 1fichier behind it, and it works with combine, but if the 1fichier backend is not overlayed with something like crypt, then "Entry doesn't belong in directory".
As not all of my files need to be encrypted, i have a folder in 1fichier with crypt, and another for the unencrypted files, and i want to mount them both with combine.

I'm thinking about what backend can i put on the top of 1fichier to make it work in combine. I've tried hasher, but no luck, as it isn't "changes" the files. Thinking about to try chunker, which i think should act similarly as crypt, but for that i also need to copy my unencrypted files to chunker backend.

So maybe you can recommend a backend, that "overlays" 1fichier, but i don't have to move all my files already in 1fichier folder?

BTW this "trick" can help understanding why combine have this bug with 1fichier?