Hey Rob,
It’s nothing out of the ordinary it’s just Huel Powder and RTD are two entirely different products. Both are nutritionally complete but one is produced as a powder the other as a liquid so there has to be differences to meet the different product demands.
It’s also important to remember that RTD is produced using industrial blenders so will always have a slightly different texture to the Powders which is mixed using a hand or a kitchen blender.