There is an open issue on the tempusdominus lib: https://github.com/tempusdominus/bootstrap-4/issues/223 It occurs when there is a valid value in a date(time) field, and the user unsets it by setting an invalid one. This rev. fixes the issue in Odoo by preventing to reach the buggy piece of code in the lib. In a few words, when the user sets an invalid date, we reset the previous valid date (which is what the lib tries to do anyway). Task 2057009 closes odoo/odoo#36211 Signed-off-by: Aaron Bohy (aab) <aab@odoo.com> Co-authored-by: Aaron Bohy <aab@odoo.com>