I'll try to be brief, but at the same time precise.
Epub book generated from azw3 by Calibre. Editing in code view.
Most chapters have <p class="msonormal2"> as paragraph header.
A few have <p class="msonormalcxspmiddle1"> instead, seemingly at random.
My normal method of dealing with this (to install my choice of justify, text indent etc.,) is to modify just the one heading in the stylesheet, then bulk replace the 'alternative' para headings. It has always worked - till now!!
(Book is 'The Art of Detection' by J.S Spicer)
Went through above procedure as normal without fault till chapter 39. Did the find/replace as before, but this time nothing changed as I saw once back in book view. Previous (changed) chapters ok, subsequent chapters ok.
Workaround of course was to modify the stylesheet for the second type to match the first. That
did change the text to my choice.
So - question - WHY? (hence the thread title).
And is there an answer? I'm completely confused as to it working in one chapter and not another.......
EDIT - I should have said that the differences in para codings was in the original azw3, not the calibre conversion....