I really appreciate the initiative you made trying to fix the pageicon6 template. in general I also feel the template could use some work. PageIcon6 is used in a lot of different pages. Changing the template had unintended consequences when it comes to tables, so I had to revert your changes. It would be better practice if you created separate PageIcon6 template and if you tested it in a sandbox. I have attempted to solve a similar problem with PageIcon2. I tried to do something similar with List of units in Civ2. I used the subst command and manually added the br between the icon and the link. That might be what you need to try.
Hmm...I understand, but it seemed to look OK in the pages I checked. If it works fine in some tables but not in others, it's not easy to test a myriad different conditions to see the exact thing causing the issue.