U+2DF5 COMBINING CYRILLIC LETTER ES-TE is not a character per se: it is one of many Cyrillic horizontally ligated combining letter sequences. As such, it should look like a ligature or sequence of its components, es and te. However, in the italic fonts, it is oblique, instead of italic as its components are.
Character data
сⷭⷮтⷵ
U+0441 CYRILLIC SMALL LETTER ES
U+2DED COMBINING CYRILLIC LETTER ES
U+2DEE COMBINING CYRILLIC LETTER TE
U+0442 CYRILLIC SMALL LETTER TE
U+2DF5 COMBINING CYRILLIC LETTER ES-TE
nizarsq
commented
4 years ago 
Font
Where the font came from, and when
Site: https://github.com/googlei18n/noto-fonts/blob/c30307083469f0c05e216ac75216fd454a517858/unhinted/NotoSans-Italic.ttf Site: https://github.com/googlei18n/noto-fonts/blob/c30307083469f0c05e216ac75216fd454a517858/unhinted/NotoSerif-Italic.ttf Date: 2019-01-31
Font version
Version 2.001
Issue
U+2DF5 COMBINING CYRILLIC LETTER ES-TE is not a character per se: it is one of many Cyrillic horizontally ligated combining letter sequences. As such, it should look like a ligature or sequence of its components, es and te. However, in the italic fonts, it is oblique, instead of italic as its components are.
Character data
сⷭⷮтⷵ U+0441 CYRILLIC SMALL LETTER ES U+2DED COMBINING CYRILLIC LETTER ES U+2DEE COMBINING CYRILLIC LETTER TE U+0442 CYRILLIC SMALL LETTER TE U+2DF5 COMBINING CYRILLIC LETTER ES-TE
Screenshot