Groups with conditional visibility applied do not appear in the form in Map Viewer if a field used in a calculated expression is missing from the form.
This issue is not reproducible and the group is showing and hiding as expected with the sample web map provided.
解决办法
Any fields used in calculated expressions must be added to the form for a group's conditional visibility to work as expected. They do not have to be editable, and users can apply conditional visibility to make them disappear, but they must be included in the form.
The group's conditional visibility works as expected in the ArcGIS Field Maps mobile app, even if the field used in the calculated expression is not added to the form.