The updates and fixes are now available! Let me know if you run into any new issues. The changes to the Voxel Editor impacted many areas of code, so I almost inevitably missed something.
The crashes appeared to be caused by a really obscure issue relating to my progress dialog. It was a threading race condition where I was updating the text label on the progress dialog both when it came into view (to default the text to "Please wait"), and when the particular process first updated it (for example, to say "Generating mesh"). So, according to the timing, it would occasionally try to update the text label from two threads and once.
Anyway, I am fairly confident it is fixed now. Before, I could continually save a model and get it to almost always crash by around the 15th to 20th save, more often around the 5th or 6th save. After fixing it, I've done upwards of 50 saves and it has never crashed once. It even inspired me to add the Ctrl+S keyboard shortcut since I was saving models so many times to test. :)