Ihor,

In an org buffer, input: [1960-10-16]
Set point between the brackets.
Press C-c ! and enter.
The result is [1970-10-16 Fri]
I expected [1060-10-16-Sun]

Yes, C-c C-c works.

But C-c ! enter is supposed to use [1960-10-16] as the default date and not change that date to 1970.

(Yes, I am replying to the correct thread which corresponds to the bug report submitted.)

On 3/22/23 10:10, Ihor Radchenko wrote:

Daniel Ortmann <daniel.ortmann@oracle.com> writes:

Since that existing timestamp at point is supposed to be used as the 
default, we definitely have a bug
==>> ... Since that 'default' time is bumped up to 1970.

Clearly, the expected default behavior is not working as expected. 
(Times after 1970 are fine.)

May you elaborate? Are you sure that you are replying to the right thread?