Huns Valen
I first became aware of this when I noticed my aircraft weren't going into "taxi" mode on landing. It was hard to chase down the origin of this behavior, but I eventually discovered that a script containing collision_start()/land_collision_start() event handlers was being TURNED OFF on region crossing... but only on rare occasions.
I might cross 20 borders without this happening, or even 50 or more. It seems like it's more likely to happen in certain areas, such as the stretch of sims starting just south of Santa Catalina and continuing east across the Blake Sea to that giant four-sim airport in the Norwegian area. I suppose if they're homestead sims, that could explain why that particular area seems more susceptible to it. That has been by far the most reliable place for reproducing this bug.
I grepped all of the scripts in the whole object for llSetScriptState() calls. There are none. (No reason there would be in the first place.)
I found that removing an llSleep() call just after a collision_start() event caused the rate of the script halting to be greatly reduced. I theorize that the chain of events is something like this:
  • Vehicle crosses sim border.
  • Occasionally, this causes a spurious collision_start() or land_collision_start() event. (This happens well up in the air, obviously, so it isn't a "real" collision. Probably a race condition between the vehicle and avatar entering the sim in some stochastic order.)
  • Something about the invocation of llSleep() when the vehicle is still actively being handed off fritzes something in the simulator; and it responds by halting the script, OR by failing to return control after llSleep()'s time has elapsed. Whatever the cause, the script's "Running" checkbox is disabled, and it is quite inert.