Occasionally, if two comments are posted on the same talk page using DiscussionTools at almost exactly the same time, one of the users will see an error message that just says "Edit conflict.".
It should be very rare, and difficult to avoid, so we probably shouldn't spend time on that. But we should improve the message to explain the problem and advise to retry.
@matmarex: Also, for sequence 6, I am noticing that, sometimes I am getting the error message "Edit Conflict" for the second user and sometimes, they just get posted one after the other just fine. Is there a specific criteria that will trigger this message?
This is expected – it just depends on the timing, and database load at the moment (that is, on whether your previous message is already present in replica databases or not).
We previously had some code to automatically retry in this case, although we removed it, because it's difficult to decide how many times and after what delay we should retry, and we have no way to actually force the replication to happen or guarantee that it did, so the error could still occur, just less often. I think this error will be very rarely seen by users in normal usage, only when two comments are posted at nearly exactly the same time, but we could probably add that back to make it even rarer.
