When I open the Factbook for Theodore of Heraclea and scroll down to Dig Deeper and click Search, it gives me
term:(biography:"Theodore of Heraclea" OR milestone:biography:"Theodore of Heraclea" OR headword:"Theodore of Heraclea" OR "Theodore of Heraclea")
That gives an error message
Unknown data type value:"Theodore of Heraclea"
So I have to manually remove the biography tags to run the search. I tried to reproduce with other people, and I noticed that there is nothing tagged biography for Virginia Chun-Nei Wong, but the search doesn't crash, it just gives some irrelevant results for other Factbook entries (like the state of Virginia). I am not sure why the search doesn't fail gracefully for Theodore, except that Logos doesn't know any more about him than I do.
41.0.416, Logos Max, Windows 11