I occasionally have the same problem with a few plug-ins, incl. Steinbergs own instruments. However, if you encounter this problem constantly I think the problem might reside outside of Cubase. Midi driver, etc, etc. I can’t remember ever having this problem with Absynth. With Zebra this was one of the reported issues for a while but several updates have been issued the last year and I thought that this was solved by now. I could be wrong about this, but check that you have the latest version of Zebra (and other plug-ins). If this doesn’t help, the “old” way of fixing hanging notes in Zebra was to change the Voice Mode from poly to arp and then back to poly. Urs Heckmann and his team is an example to follow when it comes to customer service so visit the U-HE forum over at KVR and ask any question. Sorry for using this many words and still not pinpointing the final solution.