Something I thought of and only just tested; If points have identical coordinates, then only one (the first in the choice list) of those is able to be selected in the Collect map appearance, but all are visible for selection in the select_one Enketo appearance.
What I haven't yet tested is how close items can be before they become indistinguishable for selection at the max zoom levels that the different base layers allow (I only use mapbox as the others are too limited), i.e. is this actually a problem that requires solving - are multiple selections with identical/near identical coordinates a valid use case?
The expected behaviour I'd imagine is some sort of clustering where you select the cluster and it expands to show all points at those coordinates like this:
