The remaining look mostly like name parsing problems.
The following don't parse properly and should be fixed in name parser:
Angiopteris d'urvilleana de Vriese
These are badly formatted source names:
Homozygosphaera Schilleri (Kamptner) Okada & McIntyre, 1977
The parser fails to parse it with authorship and falls back to canonical only parsing, igoring anything but the first genus name. Suggest to check the parsed name if it matches the rank during the nub build and either reject non virus species with no species epithet or just use the unparsed, full scientific name instead of the bad canonical one.
Acer √ó hillieri Lancaster
Agave √ó franzosinii Hort.Hanb. ex W.Wats.
Badly formatted IPNI names. Again only parsed to the genus with the authors parsed flag set to false.
The bad characters appear to represent the hybrid symbol as in Acer × hillieri. Potential addition to the name parser to understand that
Polana (Bulbusana) vana DeLong & Freytag 1972
Tabanus 4punctatus Fabricius, 1805
Name parser failures, needs fixed in parser!