Have you tried to set the stylesheet to include the hover selector?
Just a guess, but have you tried something like:
m_lineEdit1->setStyleSheet("QLineEdit {background-color:#888888;} QLineEdit:hover {background-color:#888888;}"); //gray
m_lineEdit1->setStyleSheet("QLineEdit {background-color:#888888;} QLineEdit:hover {background-color:#888888;}"); //gray
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Might need a semicolon after the closing brace for the QLineEdit style. I didn't test this but seems like the hover selector probably comes into play and if its defaults are different than what you are setting for the QLineEdit, it may be the cause, etc.
Hope that helps.
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