I downloaded VE Pro 5 and confirmed that the same thing is occuring. In fact, VE Pro 5 is losing more data than VE Pro 4. With VE Pro 4, I would lose data after 40 instruments. With VE Pro 5, only the first 32 instruments receive anything.

As a further test, I soloed all the instruments after the first 32, and then the CC were received for those tracks (likely because there was less CC data being sent). This strongly suggests that VE Pro has a problem with numerous CC messages that occur at the same or similar times.

@Saxer said:

i have the same problem with samplemodelling instruments (running in kontakt 4 or 5 in ve pro). i play this instrumentms via windcontroller which means there are a really lot of cc data (cc2). playing four monophonic instruments over ve pro (on the same macpro) is all what is possible. inside logic there's no missing cc-data problem, but there are cpu spikes (which isn't the case inside ve pro). nothing is perfect ;-)

This sounds like a different problem. My CPU usage on these tests is around 4% and CC data is being lost. In some cases, it is losing sustain pedal messages when they occur close to other CC changes. I'm ok with imperfection, but this makes it nearly impossible to work. I have to play things back and hope nothing important is lost.

I reported the problem. I hate to speculate, but is it possible there is a buffer that overflows when receiving too much midi data in a short time? If the data isn't showing up in Kontakt, that suggests it is being lost between Cubase and Kontak (i.e. Ve Pro). I initially thought it was Cubase, but if I load Kontakt directly, there are no lost messages.

Also, I have tried all buffer sizes in addition to various combinations of midi ports and audio ports amounts. Thanks for the help.

A buffer overrun is quite unlikely, as VE Pro can take a ridiculously high amount of MIDI messages per processing block. What could be happening is some sort of buffer limitation in the VST3 implementation on the Cubase side.

 If anyone else wants to test it, here are some project files:

(removed)

Here are the instructions I sent to support:

"I attached a Cubase project with identical clips on 16 tracks across 4 different ports (you might want to check that the channel and port setting were preserved). Each clip sets 4 different CCs at the same time. There is one VST3 VE Pro instance in the project that will likely be disconnected. Next, create an instance on the VE Pro Server and load 4 Kontakt instances across 4 ports. Load the attached Kontakt multi (monitor.nkm) in each Kontakt instance, which contains 16 empty instruments with the midi monitor script enabled. Connect the instance in Cubase and everything should be ready to go.

In each instrument in Kontakt, you can monitor the received CC messages as described in the thread (I suggest enabling verbose mode so you can see the entire log). If you check the instruments on the first two ports, they will receive all the messages. If you check the instruments on the last port, they will not receive the messages. On VE Pro 5, I received the messages on the first 2 ports, but not the last 2. On VE Pro 4, I received the messages on some of the instruments on port 3, but not port 4."

I downloaded the Cubase 6.5 demo, and I am not having the problem. I extended the test to include 8 ports with 16 instruments each, with 4 separate CC changes at the exact same time in each track. I haven't verified all 8x16 Kontakt monitor scripts, but the ones in the 8th port are receiving the data! This strongly suggests the problem was in fact with Cubase. It is strange that nobody every noticed this with Cubase 5.5, but at least it works now.