really weird wall glitch (Not barrier blocks)

When I'm riding my horse in an extreme hills biome (we all know that horses can walk up blocks like stairs) and every now and then a weird invisible wall just apparently appears out of nowhere you cant see it and it stops you from going like a barrier block but it isn't. When this happens the monsters nearby weren't visually moving but they could still hurt me and they were like 7 blocks away on the screen and also since I couldn't go past a certain point of the weird walls a creeper blew up almost killing me, when I reloaded everything I was able to pass through just fine but it's really inconsistent. It would be annoying for that to happen again if I was galloping away to heal up, so please fix that!