<html><head><style>* {font-family:Menlo,Arial}</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">Consider this code:</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="margin: 0px;">\documentclass{article}</div><div id="bloop_customfont" style="margin: 0px;">\RequirePackage{fontspec,unicode-math}</div><div id="bloop_customfont" style="margin: 0px;">\setmainfont{STIX Two Text}</div><div id="bloop_customfont" style="margin: 0px;">\setmathfont{STIX Two Math}</div><div id="bloop_customfont" style="margin: 0px;">\begin{document}</div><div id="bloop_customfont" style="margin: 0px;">$\gamma_{e}\ne\gamma_{\mathrm{e}}$</div><div id="bloop_customfont" style="margin: 0px;">\showthe\textfont4</div><div id="bloop_customfont" style="margin: 0px;">\end{document}</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">When I run this in the frozen TL2017 (LuaTeX version 1.0.4),</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">the subscript on the left gets a negative kern, tucking it in under the gamma.</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">This does not happen to the one on the right.</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">That negative kern comes from the font (character 12057).</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">The font STIX2Math.otf is Version 2.00 b137 according to otfinfo.</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">In a recent exchange with Ulrike Fischer on the tex.SE chat,</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">I have learned that this also happens with LuaTeX 1.0.6 on TL2017.</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">On TL2018, however, she gets no kern at all on either side.</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">This seems wrong. Perhaps there was a change between LuaTeX 1.0.7 and 1.0.8,</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">or it could be related to changes in unicode-math.sty.</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">Replacing \mathrm by \symrm helps (on TL2017), so I don't have an immediate</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">problem with this.</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">FWIW, the example works as expected with XeTeX.</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;">(Still on TL2017. I don't have TL2018 installed.)</div><div id="bloop_customfont" style="font-family:Menlo,Arial;font-size:14px; margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="margin: 0px;">– Harald</div></body></html>