A bunch –
`404page – your smart custom 404 error page
Activity Log
All-in-One WP Migration
All-in-One WP Migration S3 Extension
Select Blog Designer – Post and Widget Pro
Select Change Author
Classic Editor
Classic Widgets
Contact Form CFDB7
Custom Sidebars
Disable Comments
Enable Media Replace
Float To Top Button
Fonts Plugin | Google Fonts Typography
FooBar WordPress Notifications (Premium)
FooGallery (Premium)
HTML Editor Syntax Highlighter
MC4WP: Mailchimp for WordPress
Meks Time Ago
Menu Icons
Orbit Fox Companion
Page Links To
PhastPress
Popup Builder
Post Category Image Grid and Slider Pro
Post Grid and Filter with Popup Pro
PublishPress Future
Quick Featured Images
RafflePress Pro
Real Custom Post Order
ReCaptcha v2 for Contact Form 7
Redirection
Redirection for Contact Form 7
Reveal IDs
Say What?
Search Regex
Shortcode in Menus
Shortcodes Ultimate
Shortcodes Ultimate: Additional Skins
Shortcodes Ultimate: Extra Shortcodes
Simple Image Sizes
Slickstream Search and Engagement
SmartLook Visitor Recording
String Locator
TAO Schedule Update
Widget Shortcode
Widgets in Menu for WordPress
Wordfence Security
WordPress Importer
WP Mail SMTP
WP Maintenance Mode
WP Super Cache
WP Team Showcase and Slider Pro
WP Testimonials with Rotator Widget Pro
WPForms Lite
Yoast SEO
Yoast SEO Premium
Again, updating is fine until someone submits a form. I use custom html in several of the forms as well. Don’t know if that would have anything to do with it.