I have both Ham Radio Deluxe and WSJT-X configured the way the documentation recommends:
but when a QSO finishes in WSJT-X it's just not logged to HRD. Nothing happens, there's no errors. Any ideas what might be going on?
Apparently the answer was that my Ham Radio Deluxe was outdated. I found on that computer I was running an old version (not by much, maybe a month or two). Upgrading to v6.8.0.372 (13-Feb. 2023) fixed the issue.