QCompleter pop up doesn't show when in CaseInsensitive mode and model includes a string that begins with Turkish character İ (I with dot on it)

I use a completer on a line edit. The model is a qsqlquerymodel populated from a sqlite database. Model includes a string beginning with turkish character "İ". I use CaseInsensitive mode on QCompleter. When I first type "i" (It is lower case for "İ" in turkish) completion list doesn't show up. But when I first type "İ" it shows up. Also when I first type "İ" then delete it and then type "i" it shows up.