I’d like to set Segoe UI Symbol as fallback for all missing glyphs. But it doesn’t work, I get an error like registered function call [1145]: ...-14/tex/texmf-context/tex/context/base/mkxl/math-act.lmt:2339: attempt to perform arithmetic on a nil value (field 'depth') stack ... even if there’s no fallback enabled for the math font. \definefontfallback[segoeFB] [name:segoeuisymbol] [0x00300-0x003FF,0x02100-0x02800] [check=yes,force=no] That used to work, at least until version 2022-09-18. It’s completely irregular which ranges throw an error: 0x03000-0x20000 runs 0x02000-0x03000 doesn’t 0x02200-0x027FF doesn’t And the fallbacks also don’t work, even if there’s no error. It seems to depend on the font – I get errors with Segoe UI Symbol, but not with EmojiOneColor or Symbola. I checked with font versions 5.0 and 5.01, don’t have newer ones. Does it work with current versions? Also, a list of fallbacks doesn’t work (I’d like to replace single characters from different fonts); is it supposed to? test file attached. Hraban