Discovered this for the template "שחקן נבחרת" in Hebrew Wiki: https://he.wikipedia.org/w/index.php?title=תבנית:שחקן_נבחרת
If asking the API directly, the TemplateData exists and returns valid information: https://he.wikipedia.org/w/api.php?action=templatedata&format=json&generator=prefixsearch&gpssearch=%D7%A9%D7%97%D7%A7%D7%9F%20%D7%A0%D7%91%D7%97%D7%A8%D7%AA&gpsnamespace=10&redirects=true&includeMissingTitles=true&lang=he
(The above was copy/pasted from the request made by TemplateWizard through teh console, so the request itself seems to be structured properly)
However, when using the TemplateWizard dialog itself on Hebrew Wiki, searching for "שחקן נבחרת" and clicking that result, the dialog shows no fields and no description. The "Network" tab shows a request in red -- unresolved properly.
I disabled PrivacyBadger and Adblocker, so it seems like a different error, but I can't pinpoint what that might be.