@GrannyGrump: I checked TENT--SPLIT-WONT-WORK.epub with epubcheck and found lots of missing fragment ids for LOI targets:
Spoiler:
Code:
Validating using EPUB version 2.0.1 rules.
(https://github.com/IDPF/epubcheck)
June 23, 2016 12:18:20 PM CEST
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ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/cover.xhtml" (line 22, col 259):
Referenced resource could not be found in the EPUB.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 19, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 23, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 27, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 31, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 35, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 39, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 43, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 47, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 51, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 55, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 59, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 63, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 67, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 71, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 75, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 79, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 83, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 87, col 43):
Fragment identifier is not defined.
ERROR (RSC-012) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/loi.xhtml" (line 91, col 43):
Fragment identifier is not defined.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/titlepage.xhtml" (line 29, col 79):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 79, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 164, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 239, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 411, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 421, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 435, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 566, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 626, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 723, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 829, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 839, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 914, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 963, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 1220, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 1284, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 1361, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 1463, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 1540, col 61):
Referenced resource could not be found in the EPUB.
ERROR (RSC-007) at "TENT--SPLIT-WONT-WORK.epub/OEBPS/Text/TENT.xhtml" (line 1643, col 61):
Referenced resource could not be found in the EPUB.
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Check finished with 40 errors!
Did you by any chance remove them before attaching it to your post?