AdvSearchEdit - error with Polish letter 'ą'

If in the text field I enter the Polish diacritical character 'ą' or 'Ą' (right ALT + 'A' or right ALT + SHIFT + 'A'), the entered text is cleared and the character 'ą' is inserted. I cannot type the entire Polish word with the letter 'ą' (for example "zadąbrowie").

This error also occurs in AdvSearchCombobox.

I cannot reproduce this here so far.
When you set a breakpoint in

procedure TAdvSearchDropDown.KeyUp(var Key: Word; Shift: TShiftState);

(line 2081)

can you describe what happens, in particular if the Text value of the edit gets changed to ą or the text is reset to empty string?

I write the characters 'z' 'a' 'd' 'ą' one by one
Step 1
in the procedure TAdvSearchDropDown.KeyUp Text = 'z'
Step 2
in the procedure TAdvSearchDropDown.KeyUp Text = 'za'
Step 3
in the procedure TAdvSearchDropDown.KeyUp Text = 'zad'
Step 4
the text "zad" in Edit is cleared, the character 'ą' is inserted, calling the procedure TAdvSearchDropDown.KeyUp Text = 'ą'

It is unclear what is special about this character.
We do not have a keyboard here with this specific character.
We tested this with German characters like ö, ü or French characters like ô, è, ... but with none of these characters we could reproduce an issue.
Is this behavior different in a regular TEdit component?

I have checked the components below and this problem does not appear:
TEdit
TEditBtn
TAdvLUEdit
TAdvEditBtn
TAdvEdit
TDBAdvEdit
TAdvMaskEdit
TCurvyEdit
TAdvComboBox
TLUCombo
THTMLComboBox
TAdvOfficeComboBox
TCurvyCombo
TMemo
TAdvMemo
TRichEdit
TAdvRichEditor

This error occurs in AdvSearchEdit, AdvSearchComboBox and in AdvStringGrid where the default editor is:
edAdvGridDropDown
edControlDropDown
edDetailDropDown
edGridDropDown
edMemoDropDown
I also tested using the On-Screen Keyboard and this problem also occurs.

Is there a chance to fix this error?
To test this with Polish letters, just add the Polish keyboard (Querty) in the Windows keyboard settings.

I set such Polish keyboard in Windows now, but how do I reach this specific key as the physical keyboard is still a Belgian keyboard?

On-Screen Keyboard in Windows

or