This error appeared in the console for me when using the Flag module with clientside_validation installed:
VM3499:21 Uncaught TypeError: Cannot read property 'messages' of undefined
at :21:24
at :71:3
........
At the time I was editing a node and clicking on the button to report a flag.
This does not cause an actual problem unless javascript files are aggregated.
If javascript files are aggregated then this error prevents to open the modal dialog form from appearing.
Needs review
3.0
Code
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
Just wanted to inform that when you suddenly got this error on May 2024.
It was caused by this https://community.cloudflare.com/t/jsdelivr-expired-certificate-may-2024...
jsdelivr SSL Expired, should be changed into other cdn.
the config should be located in /admin/config/user-interface/clientside-validation-jquery-settings