On some pages, copying or saving “all as HAR” fails with a Cyclic_object_value error when stringifying the HAR object. Could someone more familiar with HAR take a look at the following thread on SUMO?
Hello jscher2000, thanks for reporting here
Unfortunately I’m not seeing the issue on Tout copier en temps que HAR not working | Firefox Support Forum | Mozilla Support
Since you were able to see where the error is coming from, maybe you could try to use the Browser Toolbox (Browser Toolbox — Firefox Source Docs documentation) to add a breakpoint in har-exporter.js - mozsearch and see if you can find the cyclic object in the har variable ?
looks like ZIllab filed a bug 1995746 - "Copy All As HAR" leaves the clipboard empty , we’re currently investigating