The attached testcase file demonstrates that some formatted index entries show up twice. It seems that the following must hold true for this to happen:
set1 = [Standard, LyX-Code, Quotation, Quote, Verse, Itemize, Enumerate, Abstract] set2 = [Description, List, Part, Section, Subsection, Subsubsection, Paragraph, Subparagraph (and all their * variants), Title, Author, Address] if (index_object1 and index_object2 are in distinct sets && index_object1 is formatted the same as index_object2) { wrongly output two entries in the Index list; } (If they are formatted differently, e.g. one is typewriter family and the other is in sans family, then they rightfully generate two index entries, btw.)
t1.lyx
Description: application/lyx