chmod(): Operation not permitted warning from PHP

My PHP error logs are receiving frequent (a few times per hour) warnings and the stack trace indicates the issue is being triggered by this plugin.

E_WARNING: chmod(): Operation not permitted
in chmod called at /home/mysite/public/wp-includes/class-wp-image-editor-gd.php (483)
in WP_Image_Editor_GD::_save called at /home/mysite/public/wp-includes/class-wp-image-editor-gd.php (432)
in WP_Image_Editor_GD::save called at /home/mysite/public/wp-content/plugins/schema-and-structured-data-for-wp/core/3rd-party/aqua_resizer.php (223)
in SASWP_Aq_Resize::process called at /home/mysite/public/wp-content/plugins/schema-and-structured-data-for-wp/core/3rd-party/aqua_resizer.php (375)
in saswp_aq_resize called at /home/mysite/public/wp-content/plugins/schema-and-structured-data-for-wp/output/service.php (5243)
in saswp_output_service::saswp_get_fetaure_image called at /home/mysite/public/wp-content/plugins/schema-and-structured-data-for-wp/output/function.php (3029)
in saswp_get_loop_markup called at /home/mysite/public/wp-content/plugins/schema-and-structured-data-for-wp/output/output.php (2559)
in saswp_archive_output called at /home/mysite/public/wp-content/plugins/schema-and-structured-data-for-wp/output/function.php (246)
in saswp_get_all_schema_markup_output called at /home/mysite/public/wp-content/plugins/schema-and-structured-data-for-wp/output/function.php (132)
in saswp_schema_markup_output called at /home/mysite/public/wp-includes/class-wp-hook.php (303)
in WP_Hook::apply_filters called at /home/mysite/public/wp-includes/class-wp-hook.php (327)
in WP_Hook::do_action called at /home/mysite/public/wp-includes/plugin.php (470)
in do_action called at /home/mysite/public/wp-includes/general-template.php (3031)
in wp_footer called at /home/mysite/public/wp-content/themes/mytheme/footer.php (56)
in require_once called at /home/mysite/public/wp-includes/template.php (770)
in load_template called at /home/mysite/public/wp-includes/template.php (716)
in locate_template called at /home/mysite/public/wp-includes/general-template.php (92)
in get_footer called at /home/mysite/public/wp-content/themes/mytheme/category.php (75)
in include called at /home/mysite/public/wp-includes/template-loader.php (106)
in require_once called at /home/mysite/public/wp-blog-header.php (19)

The error seems to be triggered when certain older tags or category pages are accessed, but I can’t identify a clear pattern.

File permissions for the wp-content/uploads directory (and all sub-directories) are 777 and are all owned by the site user. The wp-content/plugins/schema-and-structured-data-for-wp directory is also owned by the site user with permissions set to 775.

I have researched this issue extensively and have made several changes in an attempt to fix it, but nothing has worked and I’m out of ideas for what to do next. The error is only recorded with schema-and-structured-data-for-wp mentioned in the stack trace.

WP Version: 5.8.2
Plugin version: 1.9.88
PHP: 8.0.11
Nginx: 1.21.3
OS: CentOS 7