Once we heard back from some of our users, the issue actually looks to be with with the bookfunnelimages.com domain (and static.bookfunnelimages.com subdomain). These domains do belong to us, but they are wholly managed by CloudFlare, so I'm not sure how they could have run afoul of MB. Unless someone else had used them to host the TROJAN mentioned.
I am attaching the screenshots from Malwarebytes that we received from those users. One is in Portuguese, but you get the idea.
Please let me know if there is anything else I can provide. I've also reached out to CloudFlare to let them know there is an issue.