Z3TA+ 2.1 keeps crashing SONAR X1 Producer Expanded 64-bit build 425 and build 434

After updating my 64-bit SONAR X1 Producer Expanded with quickfix build 434, I was working on a project with Z3TA+ 2.1 (2.1.0.177 according to the latest crash data). I was getting was really bad crashes. I thought it might be because of strange interactions between Z3TA+2 and some other VSTis.

I switched back to SONAR build 425 and set up a project with a single instance of Z3TA+ 2.1. I was able to create and then freeze two tracks. I closed the project, thinking, great, it works swell now. I then tried reopening the project and SONAR instantly crashed, reporting that Z3TA+ 2.1 was at fault.

What????

Anybody else having this problem? I've been sending in crash reports to Cakewalk every time they happen. Some of them have gone on to the developers. This one is the most frustrating.