There is much lag in the Romulan mission Colloseum. It is in the Arena part. Today I quite that mission, because it was not playable. I have played the mission recently a couple of times and in the Arena part there is stuttering and rubber banding.
These lag issues are only in the Arena setting, before it and after it, things run fine.
I played this mission again the other day and had the same thing. Fine on the satellite, but once in the arena the lag was making the mission nigh on unplayable. After the first round of fighting I sat in the cage for a while and looked for bug reports, but eventually I spoke to Slamek, and the rest of the mission progressed normally.
This character is why I don't play my Romulan any more. Tovan Khev is NOT my BFF! Get him off my bridge!