submission error condition – cryptic reason message?

Situation:

Using Fluent Forms, to subscribe to a MailPoet email list.

Behavior:

A new subscriber works fine. Someone who was already subscribed, filled out the Fluent Forms email subscription form, and received the error message:
“Suspicious activity detected. Form submission blocked x”

Is this because of an “already subscribed” error condition being passed back, or something else?

Testing:

When I disable WP Armour Honeypot, the duplicate submission goes through without an error or issue. So disabling WP Armour Honeypot removes the problem.

Here’s the error message screenshot:

https://share.zight.com/01a0b4b5-3167-712a-976f-1cd9b68fa59b

(You can see the form: The subscription form is in the footer of all pages on the site)

(your own forums are overrun with spam, so I am asking here instead, thank you)

The page I need help with: [log in to see the link]