There was a bug report filed a bit ago on this (http://alpha.glitch.com/forum/bugs/1267/) but it seems to have fallen far down the list without getting a response. I also noticed it last test.
Repro Steps
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Visit a new (i.e. unvisited) area
Expected Behavior
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The amount of xp gained (x) is equal to the amount shown in the message box (y)
Actual Behavior
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x = 1.5y (i.e. x = 54 and y = 36)
To make it clear, the message says "this is your first time visiting STREET. You gained y XP." Where the XP is tracked in the upper left corner (the tube thingy), it says "+x" and you gain x XP towards the next level. This happens on all new streets.