Drinking unidentified potion brings an effect message in log e.g. "Yuck! Orcish glibber... Your vision blurs." but doesn't print a message like "You quaff lite green potion."
If potion isn't identified when drunk and you had only one in your inventory it might be challenging to recall which one it was. Especially annoying if you know for sure which type it was by message. Another reason to fix - message log looks a bit weird, there are no any clues about reason of the effect message just like it has happened without any particular cause.