c++ and qt text boxes bug with backspace key on Android

in qml and c++ text boxes like QTextEdit and QLineEdit .. etc
when I select the text in the box either by 2 touches or by moving the cursor to select the text or pressing select all from the android context menu, then pressing backspace to delete the contents the content is deleted but !
when I retype again then press space the deleted content appears again after the word I wrote
I even tried to install an event filter and handle backspace key
the filter works well and my functions deletes the selected text or the last letter but also the same behavior happens