Unflavoured/Unsweetened separating overnight?

Just made my first batch of U/U (500mls and 100g blended for 10 seconds in the Nutri-Ninja) and left in the fridge overnight.
The first thing I noticed this morning was the products had separated with a layer of brown water on top.
It’s no problem to shake it up again before use - but I’ve been using Vanilla for a couple months now and never seen it do this before.
Is this normal for U/U to do this?

sorry - I’ve just seen this was already covered here: Something wrong with unflavoured/unsweetened product