Master document inserts page breaks

I am running LO under Kubuntu 14.10. I have a master document with links to 10 files. The first file looks fine when I look at it by itself. But when I look at the master, there is a page break in the middle of a sentence. I have seen this many times. I am using no layout (I think…) and have set Formatting Aids to display everything, but see nothing unusual.

I found in the original document where the break was occuring and nothing was visible. It was between two words, so I deleted the blank and let the words run together, and saved the file. Updateing the master document showed that the page break had disappeared. Back in the original, I put the blank back between the words and saved the document. On updating the master document, all is well.

Also, LO crashes rather often using master documents. I cannot imagine not using it, tho, with 10 chapters of 10 or more pages apiece (and I am not near finishing).

Will I have to go through this sort of gymnastics often? Are master documents that problematic?

Thanks in advance for any advice or hellp.