Nodes get LOST on config change

Almost every time I change the config for a node through the web interface, the last seen delta will count up and up and up until the status changes to LOST.

A reliable way to reproduce this seems to be:
1) $ flume master
2) $ flume node_nowatch
3) go to web interface (http://localhost:35871/)
4) click "config" at the top
5) pick the node from the dropdown, use "scribe" as source and "console" as sink (without quotes)
6) click submit
7) wait a few seconds and return to http://localhost:35871/ - status should be ACTIVE and all should be fine (last seen delta <= 5)
8) click "config" at the top
9) pick the node from the dropdown, use "scribe" as source and "console" as sink (without quotes)
10) click submit
11) wait a few seconds and return to http://localhost:35871/ - status should be ACTIVE and last seen delta should increase every time you reload the page, until status eventually switches to LOST

It also seems to happen with just "console | console" and other configs I've tried. Not even sure if there was an occasion where it did not hang up after a config change...