When opening a reported changed page, the "highlight changes" view is sometimes empty until manually refreshed

[hmijail]

See screen recording:

https://user-images.githubusercontent.com/4139546/129119278-369fc673-4398-4ead-919d-f6f3a26c9efe.mov

Firefox 91 webpageScanner 2.1.0 macOS 11.5.1