can not alter table because of datatime default value

I create a table with a datatime field, it's default value is CURRENT_TIMESTAMP;

Heidisql will change it's default value to now() automatic;

When i modify some column of the table, it will raise an error cause that datetime field's default value is now()

I do not konw how to avoid this situation and why?

HeidiSQL itself does not do that, I guess the server does. However, altering the table again should not result in an error. What server version is it? And please ensure you have the latest HeidiSQL version.

i use the latest version:12.6.0.6765;

when i create tabel in command line, CURRENT_TIMESTAMP always CURRENT_TIMESTAMP; but in heidisql ui, it automatic change to now()

my sql-server version:

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if i create table from command line, then open the table by heidisql ui, the CURRENT_TIMESTAMP look like this