Pretranslation rows are sorted by ScriptureRef.CompareTo(compareSegments: true) but UpdateUsfmParserHandler uses ScriptureRef.CompareTo(compareSegments: false) which can result in missing verses.
For example, for row refs ["ISA 9:1a", "ISA 9:1a/1:s1", "ISA 9:1b", "ISA 9:2"], updating the USFM for "ISA" results in verse "9:1b" missing.