Correction:In Apocalypse, the only one she was able to "sniff out" was Angie. Carlos and Jill's partner were bitten and showing signs of infection when Alice noticed [Carlos coughed, and Peyton staggers in pain]. Angie and her were both injected, but lived normally. That might be the only type of infected that Alice is able to sense. Since LJ was bitten in this film, she wouldn't be able to sense that he was infected.
Correction: In Apocalypse, the only one she was able to "sniff out" was Angie. Carlos and Jill's partner were bitten and showing signs of infection when Alice noticed [Carlos coughed, and Peyton staggers in pain]. Angie and her were both injected, but lived normally. That might be the only type of infected that Alice is able to sense. Since LJ was bitten in this film, she wouldn't be able to sense that he was infected.