In SAM-3133 a change was made so empty values can no longer be added, Joda will default null to "now". I'd suggest to revert back to the old behavior (allowing empty values) and to improve the syncing when saving feature from SAM-3090
Excepted students cannot view the test when site-level retract date is set to if "Late submission is not accepted"
Extended Time Service should return default date if no date specified
Extended time area, extra scrollbar present after adding extended time