During my gameplay i was using mu enchantes broom in orter ro fly throw the map, it happened though that once i reached the world limit it pulled me back and showed a end of world limit message as expected, though at the same time it obliterated the existance of the broom, is that supposed to happen?
Somwtomes this happens to moving entities like you experienced. Just depends how they are coded and how fast you were traveling. There is nothing we can do about it =(. I just recommended being careful around world borders.
Which you don't notice until you hit them. Is there a chance that they might be changed so that they are visible? Like those vanilla world borders introduced in 1.8 I think. edit: Even with knowing the coordinates, I usually dont pay attention until it is too late. At least the sound was disabled a year ago.
I think barrier blocks would do a great job in terms of blocking player and entityes passage since it is "umbreakable" , though i am not sure if they were implemented by the minecraft versios of the modpack .