Focusrite Saphire Mix Control

Has anyone used the loopback feature in the MixControl? I am trying to record some dialogue from the radio. I have cubase and MixControl setup and it records without a problem but after a while, for no reason, the signal in cubase drops to a flatline? The radio(input) signal remains strong but some reason Cubase just decided to switch of th erecord button. The cursoer keeps moving but I have to re-arm the record funtion to continue the recording?

Any ideas?