If a large description is put into a forum setup page, when the summary list of forums for any given course is viewed, moodle truncates the long description, adding three dots to signify that there is more description available. Fine. But what we are seeing is that at the point where Moodle truncates the text, the table formatting is broken. Attached are screen shots showing what happens. If the text description is shortened down to just the first paragraph, to a point where the three dots do not show, then all works correctly (screen shot zero). If the text is then made longer, so that moodle truncates it, the tables are broken (screen shot one).
I can provide remote access to this moodle and the underlying server if required.