Spurious "checkpoint failure: conflict (are you replicating to yourself?)"

I'm seeing these errors in the log when couch just stops replicating (even though it appears in _active_tasks it doesn't checkpoint again, even with _replicate being called every 5 mins)
It seems to occur when replicating from a couch 1.1.1 (I have seen it on 1.0.3 machines replicating from 1.1.1)

It definitely is not replicating to itself, but I suspect it is a problem in PUTing the _local doc on the source db.

log here (snipped from host33 couch.log): http://www.friendpaste.com/3FLgRFzOEAkkKazLbc7Jgw
for that log our replication cron does an ssh to host33, then curls it to replicate from host01 to the database (with no host specified) as coninuous pull replication

We have occasionally seen slow PUTing of documents on that database (and only that database) which can take upwards of 10 seconds (via futon or our app) as it is a creaking database that has a scarred history of documents that contain many (thousands) of conflicts.
Could this occasional slow PUT manifest itself as this error in the log?

As a workaround to keep replication flowing, would it restart this replication id if the curl called the cancelling of the replication ("cancel":true) followed by the starting of replication?