I am also getting the error message on Google Recaptcha, this is on an upgrade done by CS-Cart support to 4.5.2 sp2.
I have uninstalled and reinstalled the addon, added in the site and secret keys from fresh and am getting the same "missing or incorrect code" error others have mentioned. My image_verification.tpl is exactly the same on my theme as the responsive theme too.
It's odd because I had the SIMTECH development V2 Captcha addon previously on 4.4.7 and it worked fine
Just to add to my last post. I have reinstalled the simtech development google recaptcha addon - that alone did not work, no tick box was displayed. However, when I then activate the standard recaptcha addon also it now works but passes verification.