I have just realized that Ableton filters duplicate MIDI CC messages when working on a M4L patch for my hardware synth. This causes issues with dumping the positions of my synth's knobs to Ableton.
If we just had an option to turn this "feature" off on a specific midi port it would clear up a lot of issues. A quick search on the Max For Live forum on cycling74's forum shows a lot of people running into this problem and having to come up with workarounds such as externals that access the midi ports directly but are not as stable as just getting the data from the Ableton.
I checked the behavior of other DAWs such as Cubase and Studio One and saw they do not seem to filter out duplicate messages at all so it is very strange that this only happens in Ableton.
Allow Duplicate MIDI Control Change Messages
Re: Allow Duplicate MIDI Control Change Messages
It's only been 10 years, 7 months, and 29 days since the OP, but who's counting? For posterity's stake, I have found a work-around for this problem that does not depend on any externals, and uses Max for Live only. The idea is simple: whenever a CC message comes in, send a message to an external Max for Live device on another track; on that other track sits a second Max for Live device that receives the message, and then sends emits a CC message for the same controller but with a different value. Route the output of this second track to the first, and hey presto, repeated CC messages don't look like repeats anymore. See https://github.com/edsko/eurekaprom-io/ ... multaneous for an implemented example.