In the course of my work on English Wikipedia as an account creator, sometimes an account is blocked after we receive a notification from a user that they did not request the account associated with their email address. This was the case today. As I was the account creator, I ended up getting an IP Autoblock after the account was blocked. The software should check if the account was created by an account creator and ignore auto block in this situation.
Hmm, I could be mistaken, but MediaWiki itself does not automatically blocks the IP, who created an account which confirmation e-amil is invalidated, as long as I haven't misread the code that handles the invalidation. Is it possible, that the block is made by an extension, e.g. AbuseFilter or something like this? Is there an indication in the log entry? :)