Even though anchor links don't work in all mail clients, we have still been using them in emails for tables of content in a monthly newsletter. It seems like at least a few others have run into the same problem we have, which is that Mosaico breaks anchor links:
I've found that the issue is actually because Flexmailer seems to try to apply tracking to all URLs, including anchor links, which breaks them. I've put those details here:
Does anyone have ideas how this could be fixed simply?