The single backslashes in the content of my pages are deleted (and double backslashes are converted to a single ones) in the following situations:
1) When I view or restoring a page from the «Revisions history».
2) When I change page properties in the list of pages.
The last one is wery annoying. If I change, for example, page order using the list of pages then I need to manually retype all 200 backslashes in my page (I cannot recover it from the revisions history, because there is no backslahes there too).
The backslashes are not removed when I change page content, or change page properties from the page editor.
I think I need to say that I newer use WYSIWYG editor. It is completely disabled. Any postprocessing of my texts is also disabled.