In our office we try to track pretty closely the status of the cases that we have put on the Patent Prosecution Highway. It is a rare PPH case that reaches its first Office Action without at least one problem within USPTO that requires us to poke the USPTO. Today one of our PPH cases presented a problem that we had not seen before — a big delay in examination because the USPTO misclassified the case.
(Updated on February 23 to reflect that USPTO does have a limited “reverse concordance” which maps some IPC classes to corresponding USPC classes. Thanks to Louis Ventre, Jr. for kindly pointing this out.)