Any script on a pickup that attempts to address ObjectSync will crash with the following error;

An exception occurred during EXTERN to 'VRCSDK3ComponentsVRCObjectSync.__SetKinematic__SystemBoolean__SystemVoid'.

Parameter Addresses: 0x00000030, 0x0000002B

Object reference not set to an instance of an object

If you want to replicate; Make a pickup. Give it a script that will do something to ObjectSync on pickupusedown (Eg; Set Kinematic). In ClientSim, it will crash becxause it can't find the Objectsync/rigidbody.

In-game, however, it will work fine.