Experimental advice ... but maybe we can knock some sense into it if we change around the order of the items in the bookmarks bar.
Go "Bookmarks > Show all bookmarks". In the left-hand pane, select "Bookmarks Bar". Now in the right-hand pane, drag "iCloud" down below (say) "Gmail".
Does it appear as "iCloud" instead of "iCl...d" in the bookmarks bar, now? If so, try dragging it back to the previous position. Does it stay 'iCloud"?