1. Are you using proper digital cables between mscaler and DAVE? These are supposed to be 75ohm Digital BNC. Not regular RCA interconnects with BNC adapters.
2. Do you have upsampling enabled in the streamer? If so, disable that option.
3. what interface is used to connect streamer to mscaler? Is it USB? Is the USB cable working properly? Have you tried another USB?
4. Have you tried streamer to DAVE direct without mscaler in the setup? Does the issue persist without the mscaler in your system?
please list streamer make and model, usb cable make and model, digital cables make/model, streamer settings and if you use Roon or not.
Also list Ethernet cable and setup - speed, switches, etc