This probably has already been noticed by somebody, but incase it hasn't, I thought I would mention it.
I have relatively little programming experience, but judging by the source code, (correct me if I'm wrong) it appears that PJ determines what temporary ########## file goes with the current title/artist by looking at the dates of the temporary files. A problem arises when pandora creates temporary files for two songs at the same time. A problem also can arise when pandora for whatever reason does not create* a temporary file. When either of these things happen, PJ can often puts the previo