When chatting, an incoming stanza error is not always shown to the user. This hides the fact that something is wrong.

An easy way to reproduce this is to start a chat with someone that's not on your roster, and does not exist: "Action" -> "Start a Chat" (using a non-existing JID), will cause a error to be returned to Spark (either the user or entire domain does not exist - some timeouts might need to occur before the error is generated). However, the Spark user is not notified of this error.