Reason Project Crashes Pro Tools

[spearson8]

I have Reason instantiated on 3 separate instrument tracks within a Pro Tools session.

Bass
Drums
Aux Percussion

I purchased the Reason Electric Bass refill and swapped out the existing bass with one from the refill. When I did this, the session crashed while attempting to load the new bass patch.

Tried again after restarting Pro Tools, same result.

In Reason stand alone, I loaded the session and changed the bass over manually, it saved successfully. When I loaded the newly saved Reason project within my Pro Tools session, it crashed again.

I tried creating a new Reason project within this same PT session and when I loaded the exact same Reason bass patch that crashed previously, it worked perfectly?

Is it possible for some Reason projects to get buggy and crash PT? I have no problem recreating the Reason project, but why did the first version quit functioning properly and a new one work like a charm using the exact same instruments and signal routing??