Hi,
First of all, just wanted to say that the EchoNest methods work really well and the API is easy to use.
I am experiencing the same issue as above when updating a taste profile. For me it seems that if any of the tracks can't be resolved, if I check the status too soon it prevents the ticket from ever leaving the pending status. If I check the status after a longer delay, the ticket completes and returns the tracks that couldn't be added:
"{"response":{"status":{"version":"4.2","code":0,"message":"Success"},"total_items":22,"items_updated":22,"percent_complete":100,"ticket_status":"complete","update_info":[{"item_id":"0","info":"couldn't resolve item"},{"item_id":"3","info":"couldn't resolve item"}]}}