Start Date and End Date are not associated with the fields (Date time fields do not have a visible clickable label)
https://acc-upd-ascmainsite-d8.pantheonsite.io/node/add/event
The visible label for the date and time in the Date Range part of the form is an h4 that is not associated with the date and time fields at all. Ideally all fields will have a visible label that can be clicked to activate the field.
https://www.w3.org/TR/WCAG20-TECHS/H44#H44-description.
An additional benefit of this technique is a larger clickable area for the control, since clicking on the label or the control will activate the control. This can be helpful for users with impaired motor control.
The date and time fields have hidden labels "Date" and "Time". The labels are the same for the start date and end date and this makes the labels ambiguous. Also if additional date ranges are added they also have the unspecific labels "Date" and "Time". That leads to 4 fields that a screen reader will announce only as "date" How hard is it to introduce a new attribute to the date and time fields here? We can override the current labels that get read by the SR.