This is my version of a MIDI IAC bus. Fixed my problem! Not the most elegant solution, but it works!

Now I can finally stop wasting my time troubleshooting and get back to making art. Phew!

Using PD to generate MIDI notes. Sending through IAC bus into Pro Tools. If I play a chord, the root note will be recorded far earlier than the rest of the chord. I suspect poor MIDI timestamp compatibility between PD and Pro Tools.
Funny thing is doing this via PD -> IAC -> Garage Band, it works fine.
Also, going PD -> IAC -> Kontakt Standalone Instrument -> IAC -> Pro Tools works fine too.
Any suggestions on making PD -> IAC -> Pro Tools work correctly?

@larrygus Same problem here - sending midi from PD through the IAC bus to ProTools. All my MIDI recordings are wonky and I've come to the conclusion that it's because of missing MIDI timestamp. Have you found any solutions within PD?

I'm having almost this exact issue now. Sending MIDI from PD to ProTools, then into a VST. Sounds fine when I'm playing, but when I go to record, the timing and durations are all screwy. Did you ever find a solution? I've been working on this problem for days and it's killing my creativity!!!