In 5.4 Resto Druids will be able to move full stacks of Lifebloom from one target to another. It has been slightly changed that in order to move those stacks, Druids will now have to have at least 2 seconds remaining on those stacks in order to move them.
Lifebloom stacks will only move to the target if more than 2 sec duration is remaining.
A minor change, and more than likely related to PVP that the change was made.