Object of class __PHP_Incomplete_Class could not be converted to string

Your plugin does exactly what I need it to do. Thank you.

Having some problems with an error (occasionally), though.

Using this in a WP page:

[remote_content url=”https://www.example.com/statement.html” timeout=”10″ htmlentities=”false” strip_tags=”false” selector=”pagecontent_right_inner” cache=”true” cache_ttl=”3600″]

What’s weird is it was working perfectly for awhile. Nothing changed on site.

After some time I get a server 500 error:

[Tue Jul 07 14:33:36.014282 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP Recoverable fatal error:  Object of class __PHP_Incomplete_Class could not be converted to string in /var/www/www.example.com/wp-includes/shortcodes.php on line 343, referer: https://www.example.com/wp-admin/post.php?post=1111&action=edit
[Tue Jul 07 14:33:36.015773 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP Stack trace:, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.015825 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP   1. {main}() /var/www/www.example.com/index.php:0, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.015852 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP   2. require() /var/www/www.example.com/index.php:17, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.015873 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP   3. require_once() /var/www/www.example.com/wp-blog-header.php:19, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.015894 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP   4. include() /var/www/www.example.com/wp-includes/template-loader.php:106, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.015917 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP   5. get_template_part() /var/www/www.example.com/wp-content/themes/twentysixteen/page.php:24, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.015938 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP   6. locate_template() /var/www/www.example.com/wp-includes/general-template.php:168, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.015959 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP   7. load_template() /var/www/www.example.com/wp-includes/template.php:672, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.015989 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP   8. require() /var/www/www.example.com/wp-includes/template.php:725, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.016011 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP   9. the_content() /var/www/www.example.com/wp-content/themes/twentysixteen/template-parts/content-page.php:20, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.016031 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP  10. apply_filters() /var/www/www.example.com/wp-includes/post-template.php:253, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.016061 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP  11. WP_Hook->apply_filters() /var/www/www.example.com/wp-includes/plugin.php:206, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.016102 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP  12. do_shortcode() /var/www/www.example.com/wp-includes/class-wp-hook.php:287, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.016123 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP  13. preg_replace_callback() /var/www/www.example.com/wp-includes/shortcodes.php:218, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit
[Tue Jul 07 14:33:36.016143 2020] [php7:notice] [pid 4026] [client 1.2.3.4:60040] PHP  14. do_shortcode_tag() /var/www/www.example.com/wp-includes/shortcodes.php:218, referer: https://www.example.com/wp-admin/post.php?post=5633&action=edit

After some time the error goes away and now I see the remote content again (on both admin logins and no logins). Again – nothing saved/changed on site in meantime.

The only thing I can think of for this weirdness / on/off/on again error is caching on server side. But, I have made no further changes to site during any of this.

If the error stays away, great. But at least this was reported for others..
Anyone have any idea why it would do this? Server side caching like memcache?