FSTrigger doesn't appear to honor changes in labels assignments to build nodes when polling for file changes. In my job configuration, I have "Restrict where this project can be run" set to a label ("label1", for example), instead of a build node name. I have 2 nodes with a set of labels assigned to them:

node1: label1, label2
node2: label1, label2

On the first FSTrigger polling, I see in the log that node1 was chosen for the polling and the poll was successful. If I remove label1 from node1, FSTrigger seems to not find any other nodes with label1 (From the FSTrigger Files log):

Polling started on Apr 12, 2013 10:22:47 AM
Polling for the job FSTrigger_Test_Job
Looking nodes where the poll can be run.
Looking for a candidate node to run the poll.
Trying to find an eligible node with the assigned project label label1.
Can't find any eligible nodes.
Trying to poll on master node.
Can't find any complete active node for the polling action.
Maybe slaves are not yet active at this time or the number of executor of the master is 0.
Checking again in next polling schedule.

It should have been able to use the node node2 since it also had the label label1 assigned to it. Instead, it seems to prefer to only want to use the last node that it used for the polling. If I add label1 back to node1, the polling then succeeds on the next poll.