Thanks for posting the image!
*The quick answer to your problem:
Remove the <$pagenum> block from the line controlling the chapter title from the TOC reference page.
More detail:
The "1" is the page number created by the <$pagenum> building block.
It appears there are a number of definitions that aren't being used on the reference page, so you need to do a little investigation.
First, note the paragraph style used to control your chapter title.
Then search through each entry (all the lines starting in <$paratext> for the paragraph style noted above, with TOC (e.g. ChapterTitleTOC) There may be more than one paragraph with that style.
Remove the <$paranum> building block and update your book.
Also: you may have more than one TOC reference page. The page you showed me doesn't have an entry that seems to match with your current TOC. Look for a TOC reference page (or TOC text flow on a reference page) that precedes the one you showed. You may find that it is the one that is actually controlling your TOC.
If it's still driving you nuts next week, send me the file and I'll check it out. I'll be away from email until Monday morning, Pacific time zone.