Weld Constraint keeps disabling each time I reopen Studio?

Hi again, I got custom animations working on my custom model, however for some reason each time I reopen Roblox Studio, the Weld Constraint between the Root (that contains the rig) and the HumanoidRootPart gets disabled and as a result my model just falls through the map.
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This model is currently just in StarterPlayer so I can test it out before I add more models later down the line. Am I missing something?