Sure enough, I checked and my desktop had the problematic version of glib2- glib2-2.46.0-2.
I installed the latest round of Manjaro updates, bringing glib2 up to glib2-2.46.1-1.
It's still crashing.
The new version isn't stable either. The only stable version has been glib2-2.44.1-1.
Somebody on the Manjaro forum posted this workaround:
I didn't have the option enabled in Thunar, so I checked the box to enable it. So far it is working.
Whether or not this will still work after a reboot I don't know, but I was just able to do a dozen folder & file renames without Thunar crashing.