When selecting a leaf node from the selection tree of some phenotype/medical history section, eg. "Pregnancy" or "Ear defects":
If a leaf node (ie. a term with no sub-terms) is accessible straight from the menu, and you can click it without needing to drop down any parent term, then it will behave as expected.* For an example of such a node, see "Maternal Hypertension" in the attached image.
If a leaf node is itself a sub-term to some other node (eg. "Eclampsia" in the attached image) then upon the first click it will be selected as a "YES" (as expected).* Clicking it a second time will pop out a message below it: "No sub-terms" (not expected, likely a bug.)
*Expected behaviour: Click #1 "selects" the term or phenotype as a positive ("YES") for that patient. Click #2 "deselects" the term or phenotype as non-applicable ("NA") for that patient.
Another way to get "No sub-term" is to first click on Y, then N, then Y.
This turns out to not just be an issue for "leaf" nodes but any nested nodes. All left-most nodes will deselect when clicked a second time, but none of their nested nodes will do so, regardless of whether they are parents or leaves.
Only leaf nodes show the "No sub-terms" message when clicked twice.