Solved the following issue.
https://github.com/openscad/openscad/issues/1836
The reason for this behavior is that on Save As FileName is set and it’s the same point where the customizer picks the name of JSON file to read and after reading it creates the combo-box for set of parameters. On creating Combo-box index of current selected item gets changed. So, It emits signal to recompile it.
Possible solution is that we disconnect Combo-box at https://github.com/openscad/openscad/blob/master/src/parameter/ParameterWidget.cc#L104 and reconnect after https://github.com/openscad/openscad/blob/master/src/parameter/ParameterWidget.cc#L105.
amarjeetkapoor1 