[timebandit]

I experienced a similar problem only once. I had a rather large PT session and was using sounds from Reason. At that time I was using MIDI tracks in PT to trigger the devices in Reason. After a certain point there was a very slight timing lag coming from the Reason devices. I found in that case that the timing lag went away when I exported the MIDI tracks from PT and loaded them into Reason. In other words I was using the Reason sequencer to trigger the Reason sounds. I have worked both ways (using PT or Reason to sequence) many times since then and never experienced another similar problem. I don't know why that would be - maybe something to do with Rewire throughput priority? But it might help you to try that - at least to get the session done!

Tom