Found drastic difference in moments of rcc beams with a plate modeled as brick wall partition wall in rcc frame structure

Found drastic difference in moments of rcc beams with a plate modeled as brick wall partition wall in rcc frame structure...Moments are very low on beam and column... why it happens? Is it due to stiffness of plate ,

And what is the correct way to model plate as brick partion wall over rcc beam . Should the nodes of plate connected to nodes of beam or not ?

Please suggest as I am new one to staad