Surfboard S34 Modem Interfering with X1 Service

I recently upgraded my cable modem to the Surfboard S34.  Now the picture from the X1 stb drops and pixelates frequently.  

If I power down the modem the X1 works fine. 

I don't notice any issues with the internet or streaming video over internet. 

Is the X1 service not compatible with the S34?  Do I need a specific splitter for DOCSIS 3.1 modem?