Darktable having problems exporting files after edit in raw, sometimes it exports, sometimes not, darktable locks, cpu goes to 70 Celsius

I really like this version, the new modules are amazing, but now with version 3.8.0 running on two Dell systems an I5 and I7 of older vintage, I find that after editing ANY raw fie from my Lumix FZ300, converting to .PNG or .JPEG and exporting only works intermittently, usually locks up Darktable such that I just have to kill the application. While this is happening. the CPU fan is howling and temperatures go north of 70 degrees Celsius, even after I’ve shut down Darktable. I have to shut down the computer as it never returns to a normal temperature. Almost as though some stub of the program is still running after I’ve killed the application. Both computers are running Manjaro, XFCE versions with rolling updates. Install comes from the Manjaro installer, and updates on whatever schedule the new versions are released. I also notice that regardless of how I set it in the preferences, the .xmp files are never written, even in those cases when it actually manages to export a .jpeg from the raw file after processing. I am open to changing settings, but I can’t imagine a mis-setting that would cause this behavior, and what I’m doing is very ordinary, not exotic.

This has never happened to me with any prior version of Darktable, been using it for 2 years now. I’m hoping I’m not the only one reporting this. Since it’s on two computers and started with this version, I feel it’s a bug, these are Optiplex 790 and 9020 Dell machines older but very reliable.

I’ve posted this to Github also, not sure if it’s the application or it’s integration with Manjaro.