I navigated by GPS with limited thrust 5%, and tried to set speed to 50 but it kept resetting to 350.

The error I receive at the end of the navigation right at the stop point.
end of gps error for Jawa
Caught exception during execution of script:Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
at Program.Main(String Argument, UpdateType updateSource)
at Sandbox.Game.Entities.Blocks.MyProgrammableBlock.<>c__DisplayClass45_0.<ExecuteCode>b__0(IMyGridProgram program)
at Sandbox.Game.Entities.Blocks.MyProgrammableBlock.RunSandboxedProgramActionCore(Action`1 action, String& response)