API call returning 401, other calls are not

Seems I've hit a wall, not sure how to debug this one. I have a dashboard the user goes to after login in that makes 3 calls- one to get a list of faculty, one to get a list of their classes, and one to get whether they have advisees or not. The first two seem to be fine, but the third will sometimes return a 401, and sometimes it won't when in production. When testing locally, it seems to work as expected.

I tried a lot of things that didn't seem to work, but the one that fixed the issue was setting a timeout around the fetch. However, I didn't want to set an arbitrary timeout. Has anyone ran into something similar?

Here is how I'm making the calls:

    useEffect(() => {    fetch(`${homePath}api/checklogin`, { credentials: "include" })        .then((res) => {            if (!res.ok) {                throw new Error("Unauthorized - Redirecting to login");            }            return res.json();        })        .then(() => {            setIsAuth(true);        })        .catch((err) => {            console.error("Login Check Failed:", err);            setIsAuth(false);            window.location.href = homePath;        });}, []);// get faculty listuseEffect(() => {    if (!isAuth) return;    fetch(`${homePath}api/getfacultylist`, {        credentials: "include"    })        .then((res) => {            return res.json();        })        .then((data) => {            setFacultyList(data.faculty);            if (data.faculty.length > 0) {                setSelectedFaculty(data.faculty[0]);            }        })        .catch((err) => console.error("API Error (Faculty List):", err));}, [isAuth]);// get faculty classesuseEffect(() => {    if (!selectedFaculty) return;    setIsLoading(true)    fetch(`${homePath}api/getfacultyclasses?facultyName=${selectedFaculty}`, {        credentials: "include"    })    .then((res) => {        return res.json();    })    .then((data) => {        setCourses(data.className || []);    })    .catch((err) => console.error("API Error (Faculty Classes):", err))    .finally(() => setIsLoading(false));    fetch(`${homePath}api/hasadvisees?facultyName=${selectedFaculty}`, {            credentials: "include"        })        .then((res) => {        if (!res.ok) {            console.log("RES NOT OKAY: " + res);            }        console.log("RES OKAY: " + res)        return res.json();    })    .then((data) => {        setHasAdvisees(data.HasAdvisees);    })    .catch((err) => console.error("API Error (Faculty Advisees):", err));}, [selectedFaculty]);

Backend is using claims based authentication and everything is under the same controller with an [Authorize]. I've done something similar on another application with no problems, so I don't have reason to believe it's the way that's set up.