The Sep 22 nightly has given multiple freeze-ups when using x264.
First last week after updating from the Sep 12 nightly and again this week after doing a clean install.
Last week and this week I rolled back to the Aug 6 nightly, same files, same workflows, no problems.
The Sep 12 also was problem free for the week I used it.
Maybe you can see something in the attached crash.py and admlog.
https://drive.google.com/file/d/1g133aSIetKL17zO4V37gcR_6IPZeC5qc/view?usp=sharing
https://drive.google.com/file/d/1XtiTp0Q1WO-njB70BDyNhYfh1kj44Irs/view?usp=sharing