Apologize if you were mislead, but CB Connect fires no registration triggers (it never has) so any integrations that act off them will do nothing. This is because CB Connect does a direct object store and bypasses the "saveSafely" function in CB where the triggers are handled. I'll be adding trigger execution manually in a later release.
Regarding the 500 error am unsure what could be happening. The only way to know for sure is by reviewing your server error log (please don't confuse with your access log, two different logs). Please also enable debug mode and maximum error reporting within Joomla global configuration and re-test if you are able to successfully duplicate your problem continuously.