URC’s RF was pretty sloppy back then...haven’t touched it in years. I’ve seen all the above and oftentimes had to use one US and one “i” model. Still would have some issues if same device buttons were being pressed at the same time.

I was once told by URC support, when you send a command from the remote the base opens up to all channels a brief moment. I kid you not he actually told me that. Haven’t used one since.