bad bug about split

I’ve notice a very bad bug in halion sonic about making splits. It’s quite difficult to explain so I use an example.
I made 2 sound in split. One from c2 to to 3 and another from c#3 to c4. The first sound with a plus 12 semitones of transpose. Well, if I play the d2 note and hold it, then I play d3 note (that’s another sound and another split!) the note off control affects also the d2 note, so it stops to sound!
Is there a way to fix it? It’s very bad for me!

Thank you

only me with this terrible bug??