Alt+Enter Section break not working (Writer)

Please help, I write a document splitted to sections. I have a problem quite often that new section is inserted to previous one, then I get nesting that is what I want to avoid. I try different things, sometimes Alt+Enter breaks current section and puts the cursor to empty area below. But many times not. Cursor is just stuck at same position at the end of section. It seems here is not much in documentation about section management.

Can you share a reduced sample file showing what do you describe? Edit your question and use the Upload icon (in the middle of the toolbar). Thanks.
Also share operating system and LibreOffice version.
This happen only in one file? Which type of file (.odt .doc(x))? When do this begin to happen? After an update?

Finally I could handle the problem. I had to delete all nested sections and build document again. I had one huge section spanned through rest of document that probably was causing trouble. It seems also Write has some isssue with inserting images into section, so I let images anchored outside. Now Alt+Enter works fine

If you are systematically using sections in your document, then its structure is probably wrong. In Writer, sections are primarily used to change the number of columns in a limited part of the text. The “main” number of columns is given by the page style. A pathological counter-example is the case where your document i 2- or more columns with headings extending from margin to margin (1-column). This layout leads to an extensive use of numerous sections. Whenever possible, avoid it for performance and stability reason.

If this is not your case, explain what you want to achieve so that we can suggest an alternate solution.