Delphi - missing debug info

Hello,

My delphi application is able to work with TestComplete in Keyword testing (Python), except in one single grid.

I get the error: the control cannot be recorded properly, because no symbols were found for it.

We followed:
https://support.smartbear.com/testcomplete/docs/reference/test-objects/controls/desktop/borland/string-grid/index.html

And made sure the programmer compiled with the debug mode.
I ensured both plugins were active in the TestComplete setup.

I went into object mapping and the TStringGrid was active already. We tried putting a checkmark in Derived classes - to no avail.

Did I miss something? 
Thanks.