I had a similar issue. I loaded some tokens on to a Landing page in their own rich text area. Tokens were local to the Workspace folder I was in.
The tokens appeared the first time i viewed the page. After that though, I never saw them in the previews or the emails although the tokens were in the landing page when i went to edit it.
Eventually, I tried adding the tokens to a rich text section on a different part of the page. This rich text section already had some text in there. When I added the tokens in this rich text section they appeared flawlessly.
Not sure if that helps but might be something to try!