Sending midi to Ableton Live issues

Hello,

I’m working on a patch which sends midi notes to Ableton Live acording to some random system I developed. I’ve been testing the patch with several Operator (live’s synthesizer) configurations, and I’ve found that with some of them, whenever I stop the patch it leaves the last note entry on an infinite hold; I think this is weird since its happening with just some of the synth configs and not with all of them, I’ve been wondering if it could be a Patch issue or if at least there was a method I could use to stop that from happening from Max, like some "stopnote" message I’m not aware of.

Thanks in advance.