OT:keyboard line audio + USB connected = ground loop

Anyone else have issues with pops / crackles / whines / hiss when connecting BOTH usb and audio into a PC audio interface?

Normally, the PC generates the sound via Cantabile, from my USB connected keyboard, but I also run a line out into the USB connected MOTU interface as a backup.

I’ve always had ground loop noise when doing this, so the line out goes via a DI box which removes most of it.

I’ve seen the same with Roland FP-30, FP-90 and HP-603, into different PCs with different makes of USB interfaces.

Checking if others have had/solved the same issue a different way?