External gallery links don’t work

Hello! WordPress 5.9 introduced the ability to link each image in a gallery block to a custom URL. I find that, when the PublishPress Blocks plugin is enabled, clicking images in a gallery opens them in a lightbox instead of opening the external link. This is true even if all PublishPress blocks are disabled in the plugin settings.

I’ve been able to reproduce this issue with multiple themes and hosting environments, with PublishPress Blocks being the only plugin active.