TweetPropionate is usually injected in smaller and more frequent dosages than Cypionate or Enanthate because of its shorter half-life. I believe that this is what makes Propionate less likely to aromatize. Drugs that aromatize more will cause more water retention.
Big ass dosages of Propionate will aromatize and cause a lot of water retention (I know from firsthand experience), but smaller dosages are less likely to do so.