Making a repro for this is untenable and the issue probably dependent on the full weight of the game anyway, or various other factors and I can’t reproduce this in Studio at all.
In my game Be an Alien: Renewal - Roblox there is a deep ocean. You can be a various characters. Test this with the blue snake or the default avatar because it is most visible for these. There is a custom swimming system in place that makes this issue invisible to most other characters.
When you swim in the deep ocean, either immediately or after a while after joining, a void in the water will form where physics no longer behaves correctly. The character however still thinks it is swimming.
It looks like this issue most often happens in the place shown in the videos. This is just above where the ocean slants downwards towards the deepest point with the skeleton. I’m not sure if it happens here all of the time, or in other places. It happens more reliably if you visit this area, then leave a large distance away, and then come back. The size of the affected region is not always the same, it can be a bit hard to find.
Did you ever use the Terrain tools to modify that section of water?
When the Shorelines beta came out I was doing some editing of the seabed and it caused some weird editing issues. I didn’t notice any swimming issues, but my game isn’t underwater based.
Try selecting that area underwater and fill it with water to see if that helps out.
If it helps, the affected area seems to trigger semi-reliably if I visit it, then leave (e.g. all the way across the ocean away from it), and then come back.
What does the selection box wireframe image look like when you are resizing or moving the selection box around the problem area? Does it have some sort of terrain artifacts showing in that area?
Engineers are looking at the issue. I got the impression it was related to water occupancy and potentially streaming.
@APandaPoet I’ll leave the landmarks in the testing game I provided earlier, but if someone could follow up when these are no longer needed I would appreciate it. Thanks for looking into this!
