I have two date time fields and they are made read-only based on certain conditions. this is achieved through business rules and JavaScript. One of the date time field is not editable (not able to change time part of the date) whereas the other works fine. On troubleshooting with developer tools, it appears that the disabled="true" property is set on the field that has issue and this tag is not available for the other date time field. When disabling the field on load of the form creates this issue. if the date time is not locked on load of the form, then it works fine.