Chapter numbers obscure text randomly

I’m having some issues with PTX print. Sometimes the chapter numbers obscure text as in the example shown. Other chapters work just fine, aligning correctly and no overwriting other text. I’ve changed all kinds of options but as I say, its varies from chapter to chapter so not sure if its a bug or I’m doing something wrong. Any help appreciated.

I’ve tried reproducing your issue with a couple of RTL projects here, but can’t get it to misfire. So could you please send us an archive .zip file [see button at the end of the Help tab/page] so that we can experiment with it to find the source of the issue you’re seeing. Send it to