On a Barbarian, dual wielding throwing potions of different types (strangling potions and fulminating potions, for example) they’ll randomly swap hands for no apparent reason. Sometimes, your left click will be throwing one potion, then randomly your left click will switch to the other potion.
Furthermore, sometimes the visual effects will be from one of the potions, but the actual effect will be from the other. For example, sometimes the potion thrown will look like it’s the fulminating potion, but it is actually the strangling gas potion being thrown. The little explosion from the fulminating potion will be seen, but an invisible gas cloud will be there.
This is quite frustrating because it seems to be totally random as to when it happens. You’ll be spamming one potion, then suddenly it swaps to the other potion.