When using the Batch extend due date feature and you use the feature to shift the due date by x days into the future, the preview will show the new due date as 00:00, but it will actually move it to 23.59 (which is correct). The preview should leave out the hour or show the correct one.
Nice catch! Added a see also to 25020, where we told Koha to maintain the original time of the due date, rather than changing to 00:00:00.
On master I see New due date: 10/04/2020 There is no time part (as_due_date is set).
Related to bug 25039 at the time I tested it - comments 18 and 19.
This is caused by bug 25039
Created attachment 110888 [details] Bug 26552 - Screenshots of date-times displayed Screenshots showing how dates and date/times shown when using the batch extend due dates tool - after Bug 25039 applied.