Could be?!?!
I find if i go into Program properties and then the MIDI and VST sections in my DAW, the number of options and features that can be on or off or varied in amount are huge. Made more baffling for me by my not having a clue what most of it means.
Like the instruction to be on or off of "Don't send note-offs of pitch reset messages on stop/reset" - never knew it existed or could be an issue and am not 100% understanding it.
I hope you manage to track down your particular issue on this hanging note problem.
I take it that you get this problem using a variety of different VST's?
Does it occur with a variety of numbers of notes playing at the one time, or is it always when a large number of notes are played?