The boot release on my 156GTA sportwagon no long functions from the keyfob. It works fine from the leaver next to the drivers door. All other functions on the fob work perfectly. Same result with my spare fob.
Mine did this a bit from new. I oiled what you could see of the mechanism and then just opened and shut it a few times - with keyfob and the lever near the driver's seat - and it never happened again. I suppose if absolutely nothing is happening to yours then something may be broken, but if it's just a bit sticky then this may sort it.