Mobs have weird movements and behaviour when playing on a realm

I was invited by a friend to his realm. It was a Survival realm that was on the Hard difficulty. I was killing animals for food,and then,I noticed that the animals were moving sideways,which is weird. It was night time now,and I was killing hostille mobs to defend myself. There was the issue also. They were moving sideways when they try to chase me. There was a Creeper on a small pond. I came close to it,and it exploded. I was killed by a Creeper while it was in the water. I walked through that small pond where the Creeper exploded,and I saw blocks destroyed by the explosion. Explosions are not able to destroy blocks,because the Creeper was in the water. It killed me,and destroyed blocks. If this issue is a duplicate,I'm sorry,I can't search,because I have no time. Please fix this and I will really appreciate your work.