Firestorm settings
From sNr Wiki
The following tip has been suggested, which apparently improves sim crossings when carting and prevents the crazy zombie walking.
In Firestorm, select Avatar|Preferences|Move & View|Movement.
The "Movement at region crossing" setting should be set to Stop rather than Predict.
Under "If built in LSL bridge movelock is active", select "Lock and unlock position after stopping or starting movement"