I'm sharing games from two of my friends, and both have a copy of a game I don't own (Skullgirls). When the second friend authorized their account, the games they and the first friend own (and I don't) were automatically "assigned" to them, and thus making them unusable when their library is in use, despite another library with them being shared with me.

OS
Irrelevant? (Windows 8)

STEPS

• Have two friends with the same game share their libraries
  
• Have the *second* friend (ie. the one that shared their library later) use their library
  
• Go to the Library
  
• Select a game both of them own

RESULTS
The PLAY button is replaced with BUY button (ie. the game is inaccessible due to the owner's library being in use)

EXPECTED
The PLAY button is available and visible (ie. the game "falls back" to the first friend's library).

I do realize that sharing from multiple accounts isn't very common, but is nonetheless possible and this might become a rather irritating bug.