Preserve sub-document formatting in composite document

I’d like to preserve sub-document formatting, font sizes, styles, layouts, etc in composite document. However currently composite document uses own styles to show the document and pages layout, number of pages become wrong. How to fix this or it is a bug?

This is not a bug, but something that is in the heart of the master documents idea. The master documents’ styles override those of the subdocuments.

There’s no way to disable that afaik; if you don’t need that, just don’t use master documents. I know it’s not an answer to your question, that’s why I put it as a comment.

Bad there is no such option, very inconvenient. Same trouble as in MS office. Need to have an option to use: MD style or individual document styles.

Styles cascade down from Master Document to First Document to use that style. It is thus possible to retain a style if you use unique styles in each document where they need different parameters. This may not be possible in your case but it works for me.

Master document feature is a convenience to let you spread a “unique” doc among several smaller files. Global doc formatting is expected to be consistent, meaning that child docs all use the same styles. You have it the other way round. Tweaking styles with same names differently leads to inconsistency.

If docs end up printed, without common TOC, indexes, … print them as separate jobs and assemble them physically. Otherwise no solution without modifying files.