On a development site, with all current modules, I am having an issue with trying to get views exposed form fields to stick.
I can build the view, preview it, save it, seeing the exposed filters.
After cache clear they are gone.
Rinse, repeat, same problem.
The dblog shows 2 line entries relevant:
Warning: Array to string conversion in _views_data_process_entity_types() (line 109 of /var/www/clients/client1/web1/web/core/modules/views/includes/cache.inc).
Warning: Trying to access array offset on value of type null in _field_info_prepare_instance_display() (line 385 of /var/www/clients/client1/web1/web/core/modules/field/field.info.inc).
PHP 8.0-fpm, Nginx, on Ubuntu
This issue (duplication of views definitions) has been reported in the issues queue for Registration (see https://github.com/backdrop-contrib/registration/issues/33).
A workaround is to download the DEV version of Registration at:
The DEV version includes a fix for this.
You'll need to trash the current Registration folder, unzip the above, and RENAME it to
The drawback of doing this is that Backdrop won't detect new releases of Registration if any. But you can make a note to yourself to check Registration periodically, and when a new release comes out, replace the dev version with the latest version.