what should I choose exactly with the 061 ?
The 061 code turns "digital lock" on, and 062 turns it off. This feature stops the processor from looking for analog if the digital signal is lost. When "digital lock" is on, it will still go to signal detecting mode when the digital signal is lost (after the variable delay time).
I had many many pre/processors over the year and never had this kind of issue
Well, you just didn't know that it was happening with those other processors. The SP2 shows you that it's in the signal detection mode in the display screen, so you'll know. Other processors just don't happen to let you know that it's happening. Yes, I'll admit, Bryston could have chosen a quieter relay - I've learned to ignore it.
It's essential that every digital input to any processor has to enter signal detection mode once the SPDIF bitstream signal is lost. The decoders are always monitoring the incoming signal to know when they might need to switch to PCM or AC-3 or DTS decoding. When the DSP detects any change, including lose of signal, the volume controllers are muted, and the bitstream detection and mode switching routines are started. If this didn't take place, and it allowed DTS to be decoded as PCM for example, it would sound pretty horrible. A CD player between tracks will output digital zero in PCM, so you don't get the dropouts there.
But, when you switch menus in a DVD, or pause a DVD, or change channels on a STB, the signal is lost and all the nonsense I describe above takes place. If they used a quieter relay, and didn't show you that the detection routine was running in the display, you'd never know it was happening.
You're going to have to learn to live with it. I would advice increasing the delay a bit, and short dropouts will be ignored (i.e. channel changing, etc).
brucek