Popup Maker detected an issue

This message is on EVERY site we’ve got this installed in and if we dismiss it, it keeps returning.
And yes I have checked file permissions. They are fine.

Popup Maker detected an issue with your file system’s ability and is unable to create & save cached assets for your popup styling and settings. This may lead to suboptimal performance. Please check your filesystem and contact your hosting provide to ensure Popup Maker can create and write to cache files.

Please fix this bug. And I have no doubt it IS a bug. We don’t even have caching on all these sites, and the only common ground is Wordfence and Generatepress. and perhaps the web host.