This is more of a documentation task than anything, but Timeless doesn't seem to understand cellpadding. I personally don't have a problem with this behavior (it will help identify off the cuff where changes should be made to bring Wiki* into the 21st century of HTML), which is why I'm noting it as documentation, but I might reasonably suggest this will be unexpected. 🙂
- Vector: A table with cellpadding in wikitext
- Timeless: The same table with cellpadding in wikitext
- Vector: A table without cellpadding in wikitext
- Timeless: The same table without cellpadding in wikitext
There are some other rendering differences there too on Firefox 57 on Windows 10, but that one immediately jumps at you.