QKeySequence ( selectall/cut/copy/paste ) are not handled on QLineEdit once a context menu is requested on it, rather they are passed over to MainWindow

I have a QMainWindow on which I have installed some triggers ( select all, cut, copy, paste etc. ), I have a several QLineEdits on the same application.
If I request a context menu on any lineedit, and then bring back the lineedit to focus, it fails to accept/handle any of the shortcuts ( means if i perform a select all( ctrl+a ), cut/copy etc. ), it happens on the mainwindow itself.

It can be easily reproducible on the mock application i have attached.
There is a selectall trigger installed on the QMainWindow, which selects the content on the topmost QTextEdit field,
now you start entering something in the QLineEdit below the text edit and request for a context menu on it and then try pressing ctrl+a, it selects the content of the TextEdit above the selected/focused LineEdit. ( Same happens with the cut/copy/paste as well, can't see it here since I have not installed those triggers on mainwindow ).