Page1 "creeping" into further pages in the document

Writer, English
LO Version: 4.2.1.1
Build ID: d7dbbd7842e6a58b0f521599204e827654e1fb8b
Windows 7, 64bit, English

I have a text file with many chapters and sub-chapters and ToC. The ToC is based on the style assigned to headings (heading 1, heading 2, etc).

After preparing the first sub-heading (for the first sub-chapter), I copy this heading around to make additional subheadings. Now in my ToC I have:

  1. Chapter 1…4
    1.1 Sub-chapter 1/1…4
  2. Chapter 2…1
    2.1 Subchapter 2/1…1

Chapter 1 starts at page 4, chapter 2 starts at page 9, but when I go to chapter 2 in the document, in the bottom left corner I see the page number as Page1 9/20 instead of Page 9/20 and the ToC reflects that situation.

How to resolve that problem?

Honest warning: If you advise me to select all and remove formatting this will be the last second I will ever use this soft. I already went through this process for other ToC related problem…

Do you have set any page breaks manually?