Writer margins change when opening

Using LO 5.1.0.3 on Windows 7;
I create a new Writer document, format margins, etc., save, and close. I have disable ALL auto-correct and auto-type functons.
When I re-open the document, the margins have changed. They aer neither the defaul template margins, nor the margins set on the document prior to saving.
Also, as part of the document, I have several lines of underscore, serving as a form for hand-writing information. Each line was originally one space short of the margins on each end. In the re=opened document, the lines now wrap several characters into an additional line below - more than the amout of margin change, adding a page to the document.

Anypne have any ideas? I’ve been fighting this for several days now.

Thanx, in advance!