Do you have applied a Character Style to those paragraphs?
Character styles should never be applied to the whole paragraph, only for exceptions in format or language.
Hmmm, it looks like there are Character Styles involved, but not sure how they got there.
The text styles that I am changing are in a TOC. When I made the TOC I selected "new paragraph style" for this level. And made a paragraph style "TOCChapterHeading". Now I want to change "TOCChapterHeading" and have it reflect through the entire TOC for that level. But I am having the trouble described above.
You ask about Character styles. Well, just checking, there are Character styles defined. It is called Chapter-T. But not sure how they got there as I just made this TOC. The Character style goes across the entire line of the TOC entry (all the way to page number.
Should I set the Character styles back to [none] before changing the paragraph style?
Local formatting and character styles applied to the text in the corpus of the document will carry through to the TOC. If you need to modify text in the corpus, but not in the TOC, you should use nested character styles or GREP styles applied as part of the paragraph style in the corpus.
Probably the source text in the headline has a Character Style applied. The general use of Character Styles should be avoided. Often people are applying Character Styles to the whole text, either because they have learned it when they started to work with Quark Xpress and carried this praxis over to their handling of InDesign or because the document has been converted from a Quark Xpress file and normally these texts have applied Character Styles everywhere.
I would recommend to go through your document and check if there are Character Styles applied, even if they are not needed. Click on the [None] entry in the Character Style panel.