Have you had a beautiful table that has taken hours to create, merge or split a cell and suddenly the right edges are jagged? No matter what you do, the right edges of the table are jagged from that point on!
No, I haven't found a way to salvage that table, but I think I have found a way to prevent it from happening. I have been adding a column to the end of my tables -- as small as possible (.125). Removing all cell borders from that column so it is unseen to the user. THIS COLUMN MUST NEVER BE USED. That is the key. Don't add text, never merge this column, etc.
So far I've had no jagged edges using this method!