It's already well known that in realms, there is terrible lag, and that placing blocks quickly in realms is basically impossible (at least where I live in europe, which does has good internet speeds), because only every other or every third or fourth block actually gets placed except when it is the first block placed since a while (and this all shouldn't even be a problem),

but what makes even less sense to me, is that the rotation of a block (such as a terracotta block) that actually succeeds in getting placed, might not end up being rotated in the way that you placed it in; in the way you want, if you have just rotated your player before placing the block. It's as if it remembers your rotation from a few seconds ago, instead of sending the rotation of the player/block along with the block, inside a single packet.