Strange edit issues on TAdvcgrid


since a while (one or two months) I get strange issues with the tadvcolumngrid.
Some times I can edit cells which should not be editable. I using the CanEditCell event, the canEdit var is fales, but still sometimes (it doesn't happen a lot) I can edit this cell. Mostly it is when I navigate in the grid from a TAdvEdit (linked in the grid using a TFormControlEdit) to a cell in edFloat format. The order of the columns had something to do with this problem. When I move the float column to another location, i'm no longer able to edit this column.
From time to time a text is show in the wrong column as well. I place the text in the grid using columnByName and it appears in the wrong cell.
I think, but I'm not sure of this, that the grid from time to time does not count the fiexed column on the left.
What can cause this behavior? How can I solve this issue?

I have some more information on the canEdit problem.

I'm using the canEditCell event, I'm 100% sure that i return CanEdit false.
When I debug in the advgrid source code, the TEditLink.EditKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState); event in the advgrid source code does post the VK_F2 message
PostMessage(Handle, WM_KEYDOWN, VK_F2, 0);