I've had this bug too on occasion - found out it's actually not a Freelancer issue, but a Windows issue. I used the numpad to strafe, and when I accidentally tap off the numlock the keys freeze in their last configuration. This can cause the strafe key to "stick".
Solution: Tap the key bound to the strafe direction you are going in to clear the stuck key.
Wide awake in a world that sleeps, enduring thoughts, enduring scenes. The knowledge of what is yet to come.
From a time when all seems lost, from a dead man to a world, without restraint, unafraid and free.
Mostly retired Discovery member. May still visit from time to time.