It does not look like a general issue, it seems to me like a 3rd party CSS rule is causing it.
I can only confirm if I can see the at least the front-end.
Looks like some kind of negative margin, padding, position or floating applied to the fieldset element maybe from the theme or anothe plugin CSS?
But that's just a guess, it might be something else. If I could see the problematic url I might be able to determine the cause.
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