As the title says, when a HumanoidRootPart’s CollisionGroupId is set to one that doesn’t exist and never has existed in the current DataModel, it causes it to not respect the HipHeight property of its respective Humanoid.
Here’s a video to demonstrate what I mean:
Disregarding that the HumanoidRootPart appears to zoom off into horizon (that’s a totally different issue), you can see that there’s a very clear difference in behavior between the normal and bugged Humanoids. Attached is a model containing the 4 humanoids in the video:
humanoid-glitch.rbxm (4.2 KB)
To make this happen without the models:
- Open a new place to ensure there’s no issue with Collision Groups already being defined
- Make a humanoid of either R6 or R15 with any positive non-zero HipHeight
- Change the HumanoidRootPart’s CollisionGroupId to 1 instead of 0
- Watch as the Humanoid falls to the ground in complete disregard for the HipHeight property
This is easily solved in-studio by opening the Collision Group Editor, creating a group with the same ID, then destroying it. After that, it won’t happen even after a save and reload.