Chapter Numbering in a RTL language

Hi
I’m using libreoffice 6.1.3.2 and i found a weird behavior(maybe a bug) in Chapter Numbering:
In a right-to-left document (like in persian/farsi or arabic) the order of Headings level are still left-to-right.
I’m not sure if i make a sense here, but for example while i’m expecting this order:

1
1.1
1.2
1.2.1
1.2.2
1.3

I get this:

1
1.1
2.1
1.2.1
2.2.1
3.1

But of course my fonts are set in persian and my paragraphs are right justified.
As a workaround i’ve found in Chapter Numbering dialog if i choose Number type for first level something like native or arabic and for the second level farsi and so on (choosing like this alternatively), the numbering goes well!
image description
So i want to know if this is a bug or i’m doing it wrong?
Thanks.