I have implemented my own (very simple though) QStandardItemModel-qtableview.
Well, no you haven't. You've implemented a QWidget, which for some strange reason you call ParameterModel, and which contains public member variables of types pointer to QStandardItemModel and pointer to QTableView, along with a bunch of pointers to child widgets.

Then, floating out in interplanetary space, you have a pointer to a QVector of pointers to ParameterModel instances, and in another piece of interplanetary space, you have some code that uses a pointer from that vector to access a model that you set some data into.

You don't bother to show us how you create that vector, how you create the instances of the ParameterModel widgets inside it or the children of those widgets, how you arrive at the model_index, row_index, and column_index values for the item you are trying to change. Just code floating in space, drifting along, trying to stay out of the way of planets, asteroids, and comets as it spirals into the Sun...

How are we supposed to be able to understand what might be wrong, much less help?