“ This is because:
the automated matching algorithm isn't perfect, especially around hyphenated words the original proofreading may be against a slightly different edition or contain formatting that isn't suitable for the Page namespace. Normally, the work needs to be re-checked on a page-by-page basis. It's usually easier to correct issues like cross-page hyphenation and formatting before splitting the work.
See also The job queue can be seen here : https://phetools.toolforge.org/match_and_split.php. Jobs are processed singularly for Match and for Split. ”

“ Have the header and footer fields in the Index been appropriately set for the running header and footer? When Page: namespace pages are created the contents of these fields is used to populate the header and footer fields. When not to use this tool If any of the above criteria are not met If the text has been pasted from Project Gutenberg or Distributed Proofreaders, then we do not know that the editions used are the same. Side-by-side proofreading should be done on the OCR text layer in the Page: namespace and either transcluded to replace the pasted text or transcluded as a separate edition. ”