I am currently having issues with lag on my realm. The lag only happens  in chunks where we have built. Not rubber banding, but mobs movements are jagged and slow; arrows (and any throwable items) are delayed; and when we try eating the animation will play, but the food isn't being consumed (food pops don't replenish and the number of food items doesn't change). Other players are having issues with flying the elytra. 

I took the world save off the realm and the world played smoothly on multiplayer, it just seems to be an issue on the realm. 

I tried closing and opening the realm and also re-uploading the save onto the realm, but none of that help - only made the lag worse.