What erratic behavior? Have you posted about the specifics on another thread?
Yes, I did post specifics on another thread but I can't find it now. Here's a summary again though. Some of this is erratic behavior and some of it is just 20th century primitive. By the way, most of the time I'm listening to either MP3s on USB sticks or the jukebox, or standard music CDs.
1. When I first switch on the car the audio source usually sets itself to the last one I used (USB stick or CD), but the system frequently takes too long (20 - 30 seconds?) to recognize those sources and switches to FM radio instead. For some reason this seems to happen more often if the car has been switched off for only a very short period of time - for example, switching off the car for a minute while I run into the Post Office to mail a letter. This is irritating if I'm running around all day making short trips between stops.
2. The audio volume when I switch on the car is inconsistent. Sometimes it's where I left it, sometimes it's almost (but not quite) muted. The latter is annoying if I'm listening to MP3s or CDs because the music continues to play and I miss parts of it until I either realize that it hasn't come on or notice the very quiet background noise of the almost-muted music and turn it up again. It's even more annoying if I'm listening to an audio book and miss chunks of the text then have to scan backwards to find the right place.
3. Even when the system does recognize the USB stick and sets the volume correctly it sometimes takes 1 - 4 minutes before it shows a track listing, and until that happens I can't switch tracks or albums. This happens even if the same USB stick has been in place for several weeks.
4. The 10,000 file limit prevents me from putting all my music on a single USB stick in MP3 format so I split it between two USB sticks (128GB and 256GB) and the 40GB hard drive (5,000 file limit). However, when I switch USB sticks it takes a ridiculously long time (up to 45 minutes) for the system to find, list and add all the files to its database so I can fully access them. I've tried several brands of USB memory sticks, high-end name-brand and generic, with capacities from 4GB to 256GB, and they've all had the same issue. Also, with a 40GB hard disk for storage space it seems like the system should be able to recognize, store and maintain more than one USB database rather than building a new one from scratch every time the stick is switched. Because of the long database rebuilding time I switch USB sticks much less frequently than I otherwise would do.
5. Transferring files from a USB stick to the jukebox takes a very long time, and if you interrupt the process by switching off the car it restarts the transfer from the beginning. To avoid this problem I had to transfer the files in small batches over the course of several days - put a few file folders on the USB stick, transfer them to the jukebox on my next trip, then delete those files from the USB stick and repeat the process with a new batch on my next trip.
6. The music search function is primitive as well. After you've entered four characters it locks you out and does a search on them, then it allows you to add one more character and updates the search results, and so on.
The PCM software update back in February made no difference to any of the above issues.
Also, as I mentioned in another thread I offered to let some friends borrow my Macan for several days for a road trip if they ever wanted to do so, and it dawned on me that I'd probably spend more time explaining the various shortcomings of the audio system to them than everything else put together. The Macan itself is great but Porsche should be embarrassed by its PCM system, at least the one in the 2015 cars (maybe 2017 Macans with the new PCM and two SD card slots are better). I don't need the latest and greatest technology for my music, but whatever the system does it should do consistently and predictably.