Ahh, I see, the way coordinates are saved changed in v2026.1.
Previously, there was no space between two coordinate entries; they were separated only by a semicolon:
19.53545266559179 -50.42645417153835 0.0 0.0;-10.748231888662367 -45.33697362989187 0.0 0.0;-0.8309302882938091 -12.323532029986382 0.0 0.0
Because of that, count-selected treated it as 3 elements in each point, as explained in:ODK geofence (v1)
Each geopoint actually consists of only three list elements, because the accuracy value of the previous geopoint is prepended to the latitude of the latter, eg "0;-40.550261", except for the last geopoint.
Currently, there is a space and count-selected sees 4 elements in every point which makes more sense.
@Edmonds As I said above, please update your constraint from (count-selected(.) -1) div 3 to count-selected(.) div 4.