Error: “There is no valid unit tag.”

I’ve seen this somewhat answered in a few topics and Github issues already, however I’m still running in to this error no matter what I try.

I currently am appending to the FormData a new property like this:

const body = new FormData();
const formId = 'xxx';
...other properties
body.append('_wpcf7_recaptcha_response', recaptchaToken.value as string);
body.append('_wpcf7_unit_tag: ', 'wpcf7-f${formId}-o1');

The format of the value for this new property I got from this Github issue. When submitting, I still receive the 400 error “There is no valid unit tag”. I have also been unable to find any documentation regarding this, and only vague references to it in the release notes. I’m not sure if it makes a difference or not, but I am using WordPress as a headless CMS, and am submitting to the api via a Nuxt3 frontend.

How do I resolve this issue?

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