Some Empty Email Tags Showing Up

For over a year now, a select few tags in our email are still showing up if they’re not filled in. It skips about half of them, but still shows the same four, all bundled together at the bottom like this:

Meal? [meal2]
Pickup: [pickup2]

The only ones that seem affected are required checkboxes, and one non-required dropdown. Other dropdowns are not affected. I did note that by some fluke they all seem to be ones that do not have a dash in the field name, but changing that didn’t solve it. I also tried making them non-required, which also didn’t fix it. Out of nine items, there are four that insist on being in the email every time. Each email has similar information three times, and the same four show up in all three items (so [meal1], [meal2], and [meal3] will always show up in the email). Our event only runs once per year so last year we just lived with it, but it does confuse some of our participants. The plugin is up to date. We are also using the multi-form add-on which is also up-to-date. The behaviour hasn’t changed since we ran at the same time last year.

Thanks!