Since the Rossini had front-panel transport controls those were mapped to the same functions in Roon and UPnP. The remote uses our standard transport control commands which map to those functions as well. Since the Rossini DAC and Player run nearly identical software those commands are preserved in both products.
The upsampler doesn’t have any transport control functions exposed via IR since in a system that has the transport, the remote would end up controlling both simultaneously.
We’ve had to make some adjustments to the way that everything works when a Rossini Transport is connected to a Rossini Player or DAC and have added intelligence to decide which device ends up paying attention to the IR remote. This logic could be applied to Vivaldi, but isn’t on the roadmap yet. I would personally welcome the change and am pushing to get the behavior changed in a future update.