As an example, I go to https://www.inaturalist.org/listed_taxa/43474370, click Edit next to Establishment Means, then click Cancel. Then the Establishment Means line is gone.
just when editing without saving right?
Correct, it hasn’t happened to me when I save.
I can replicate with your example and with others. Workaround for now is just to refresh the page in the browser, and it comes right back.
I can replicate as well, I’ll file a bug.