I also reported this issue to Adblock Plus on 6/1 (status still marked as "unknown"). In the meantime, as Ellen indicated, an individual can disable the ad-blocker for the WikiTree site (though that's only a work-around on a user-by-user basis).
I typically use non-subscription sources in WikiTree profiles when available, but that's not always possible. When adding Ancestry.com links to source citations here, using an Ancestry external link template prefixes the Ancestry.com link with WikiTree's affiliate link, which appears to avoid the issue at this time. Using such a template can also "future-proof" the links in case Ancestry changes their URL structure in the future - the template can usually be updated to resolve all the resulting broken links that utilize the template.
Having said that, I believe that the best way to include a link to an Ancestry.com record/image in a source citation here is to use an Ancestry publicly sharable link, which subscribers can use to share Ancestry.com records/images with non-subscribers (I use the Twitter option just to copy the link so I can use it elsewhere). There's not an external link template here for Ancestry shared links (I'm not sure there's anything meaningful in the URL, as there is for other Ancestry.com links). Like the other Ancestry.com links, the shared links would also be hidden by the ad-blocker due to the current problem. But I've found that if I prefix the Ancestry shared link with WikiTree's affiliate link (copied from what an Ancestry template generates), this also appears to avoid the issue at this time. This can be done by adding the following snippet to the beginning of the Ancestry share link: