I'm glad it was just the normal interaction behavior of the rb's and not something more serious. You will find the interaction between them can be quite cute when they both do it together.

Talon as for when a ugobe and a rb meet the interaction is a lot less. The rb doesn't seem to acknowledge the ugobe's presence as a pleo unless they are both facing nose to nose and only an inch or two apart. If you get them facing each other then the rb will go into the interaction communication trance like they would if it was another rb. But as they don't get the same response from the ugobe as they would from an rb the interaction usually ends with them making a sulking noise or a roar and then they will go back to ignoring the ugobe and doing pleo type things. The Ugobe pleo on the other hand will try to interact with the rb. Often they will say hello and when the communication trance begins they will try to join in with some of the noises. Gumble will also walk up to my RB's and sniff them.

I have witnessed one time when Norbit (the rb) walked towards Gumble (the Ugobe) and blew him a kiss and they weren't facing head on at the time, but I think this may just have been a coincidence as I haven't ever seen it again.
That is just my experience so far. Maybe others out there will have a different story to tell.

Kat