A C6678 IPC interrupt question

Hi all,

I meet a problem with the IPC interrupt,  i writed  IPCGRx to set up a interrupt  to corex.

  when i set a  specific vector id except for the 4th vector id, the  target core will enter twice interrupt ,

i have check the IFR register , the bit Corresponds to  the 4th vector id will always be set up regardless of  the specific vector id i used  after i writed the IPCGRx of  the target core , i don't know why ? can anyone help?

Thanks ,

fan shi ding