There's been some work recently to standardise on the use of .generaltable for "general tables" where previously all sorts of different classes were used.
The flip side of this is the inappropriate use of .generaltable on tables that are used purely for layout purposes.
The more that people see .generaltable used consistently the more likely they are to assume they can make changes to the .generaltable class styles that make sense for general tables but that don't make sense on layout tables.
Some of these "tables" also have other classes with the word table in them, which are equally open to mistaken abuse. Maybe those can be fixed at the same time, maybe they need their own bug.
The assign roles page: /admin/roles/assign.php?contextid=2&roleid=1
The group edit page: /group/index.php?id=1
The add users to group page: /group/members.php?group=1