ahaha... I've just tried Delphi (10.3) and VCL TCheckBox doesn't have OnChange event at all!
now you see why it would ok for a LCL developer to suffer from a substance abuse
But technically the report is incorrect.
If we're seeking Delphi compatibility, THEN:
changing State via code should trigger "OnClick" event.
changing Checked via code should trigger "OnClick" event
(you can check that, and if it's not this way, you can surely file a bug report with the reference to Delphi compatibility)
Triggering event of OnChange is so solely in LCL responsibility. So, it should be strictly documented (in LCL documentation) and/or Requested For Comments (with the future documentation).
If it's documented, we can accepted the current behavior as expected and desired, and the bug report was created without any base. (solely on the developer's expectations). And should be closed as "no changes required".
P.S. The most sad thing for me, personally, is that LCL is out there for about 20 years now. But we're still have to handle such basic stuff as checkbox notifications.