sound behaves different when used in a multi

[clockworkpictures]

Hi all: I got back my baby, a wonderful TI2 after staying apart for too many years ^_^

I'm not a synthesis guru, but definitely not new to that either: I'm experiencing something I can't still figure out and I wonder if somebody here may help.

For my band I've programmed some sounds and for a specific song a couple of those are arranged in a multi, split-layered, playing on the same midi ch.

one of the two (essentially an efx) has a very long decay: it plays out correctly when played as a single, but when played in that multi the decay shortens quite a lot and the sound in general behaves very differently. I'm attaching a recording: first sound played is when it is used as a single, second one is the same sound playing within the multi.

I've been diggling again and again into the multi edit pages, but with no substantial result: any idea?

thanks in advance ^_^