This is another bug we haven't been able to repro, but I _think_ I've narrowed down the cause and hope the next build will be fixed. If it doesn't have the fix, the next build will at least have crash reporting so I'll be able to get a stack trace and really narrow it down.
Thanks for the report and sorry that it's crashing for you. The next public build should be on here July 11th if you want to check back then!