Cool, thanks for the report.

You can downgrade from here: https://addons.mozilla.org/en-US/firefox/addon/live-recorder/versions/ (and toggle off auto updates for this add-on from about:addons), meanwhile I'll try and see if I can find & fix the bug soon.

Could you tell me, which version of FF are you using? And more details on when this happens (during recording? during download?), how and how often it happens (every time?), would make it easier to find this to fix this.