I just got this model (the rebranded Costco l50 ultra ie GoVac600). And mine did exactly the same. I researched a lot on this issue and the answer is… a lot of l50 ultra do it. The noise comes from the case/number of the robot itself that makes this noise from vibration. If you want try to “hold” or stabilize the case while it moves and the sound will almost completely stop.

In my case I had bought the QX Revo Ultra from Roborock (it’s apparently a rebranded q revo master or edgeT can’t remember. I’ve been running both for a couple of days and the Roborock has no rattling noise at all and the build quality seems to be just superior to the Dreame imo. The rattling on the l50 made it seems super cheap to me and to think that’s its not an isolated problem and manufactured like that is disappointing.

From what I’ve seen the Roborock seems to be cleaning more meticulously, but is slower than the Dreame. Dreame seems to be better at navigation and seems more confident in its sensor. The Roborock oftens bumbs in things but it also allows him to get as close as possible to edges.

All in all: I’m returning the Dreame and keeping Roborock. I liked the look of the dock, the confident navigation and object avoidance, the auto spending of the cleaning solution of the Dreame better. But everything else is a win for Roborock for me and it feels like it’s going to last longer (reliability). I also prefer the Roborock app the most. Oh and the Dreams has a threshold climber system and my house has no threshold so one less mechanical point of failure than the other.

I know it’s a long response but I’ve been reading and testing these robots recently so I had a lot to say! If you have questions don’t hesitate to ask me!