Multiple Plug-in Instance Issue In Pro Tools

Hi all. I have a plug-in which is creating some mild digital distortion (almost akin to clock noise) when two or more instances of it are running in Pro Tools. Interestingly enough it seems Pro Tools exclusive - no issue with VST versions in any DAW.

I have gone through the forum and made sure I am not using any global or static variables. Anyone with similar experience or thoughts? Thanks!